Bank 

A schedule organized for tight connections where a series of flights arrive and depart closely timed together to facilitate short connections. Frequently banks are geographically organized.
“IAD has 4 banks”. 

Beyond Revenue 

Airlines sometimes consider the revenue of the whole trip when considering the profitability of a single flight. On DFW-MSY, for example, there are passengers flying LAX-DFW-MSY. There is a school of thought that is largely now discredited that the revenue on LAX-DFW should also be added to DFW-MSY because you don’t get one without the other. While it is logically true, it results in bad decisions typically. It makes short routes fantastically profitable even if they are empty, for example…and generally counts all connecting revenue twice which is dangerous for network optimization.
“The conduit flight has a ton of Beyond Revenue” 

Bank Break 

The earliest flight departing from the bank. This sets the arrival time of the last flight into the bank unless connections are sacrificed. If the MCT is 25 minutes and the bank break is at 0845, arrivals after 0820 will not fully connect.
“DLH is the 0845 bank break.” 

Block Time/Taxi In/Taxi Out/Air Time

 lock time is the number of minutes gate to gate a flight is scheduled for. Taxi Out is the time from the gate departure to wheels up (off the ground). Taxi In is wheels down (on the ground) to gate minutes. Air Time is wheels up to touchdown. Change-of-Gauge A connection masquerading as single plane service assigned a single flight number. Similar to Funnel Flights. Usually change-of-gauge refers to a single equipment change on a long-haul international flight connecting to another flight but using a single flight number.
"We have a round-the-world flight on a single flight number, but it is really a bunch of change-of-gauges"

 Circuity

 The ratio out of the way a connect is versus a non-stop if one existed. If a route is 500 miles non-stop and a connect between the same cities was 400 miles for leg 1 and 600 miles for leg 2, the circuity would be 2.0 ((400+600) / 500).
“Circuity is too long on that connect, block it with the fare rules” 

Conduit 

This is a reference to an electrical drawing, but a route between two of the airline’s hubs is called a conduit because it “sprouts wires on both ends”. The wires are metaphorical, but actually connecting options.
“We need bigger planes on the conduits” 

Connect Points 

Each fare has filed with it a list if valid connect points. If a fare from ABE to MIA is filed the connect points would probably exclude DEN as a valid connect because it allows too many miles to be flown.
“Those flights don’t need to connect, it’s not a valid connect point” 

Departure Sequencing 

At a large hub there is usually an operations rule enforcing a limit on the number of planes that can depart or pushback in a time band. This is done both for runway capacity and limits on the number of planes that can be pushed back at the same time.
“Each departure should have 2 minute departure sequencing.” 

Fair Share 

The process of QSI figures out a route forecast that is indicative of Fair Share. This means it does not include airline preference. The difference between reality and QSI is airline preference, or Share Gap.
“We do well on Fair Share, but we are getting our butts kicked in Boston” 

FAM

After flights are scheduled which is often done by hand, a Fleet Assignment Model is often used to determine the optimal aircraft for each flight or line. The FAM forecasts or uses historical load information and sets the equipment types to maximize profit margin. Modern FAMs can string together lines of flying on a type. but usually have some orphans at the end that need to be manually changed to fit without wasting aircraft utilization.
“FAM the June schedule.” 

Forced RONs/Required RONs 

Minimum RON count at a station typically because it is a maintenance base.
“We have 4 required RONs at TUL.” 

Fully Rotating Schedule 

Typically all planes in a fleet type are scheduled to rotate so that in theory a flight is flown by a different tail every day until the whole fleet type cycles. Some airlines don’t do this, but is extremely common in the USA. In reality, full rotation rarely happens because of maintenance swaps and irregular ops. But that creates difficulty with heavy checks because planes are not reliably picking up the same number of hours each month.
“The 737s have a fully rotating schedule.” 

Funnel Flight 

A series of change-of-gauge flight numbers all attached to a single flight, usually a long-haul international. Also called a starburst. LHR-EWR-DCA/BOS/MCO/etc on separate single flight numbers appearing to be single plane service when they are really connects would be a bunch of funnel flights. This concept is largely gone in the USA.
"The Heathrow flight needs to have funnel flights added" 

Gate Separation 

Gate separation is a rule of how many minutes are allowed between planned uses of a gate. 15 minutes is fairly common, but it has been growing.
“Check the gate separation at SDF.” 

Gauge 

Aircraft size reference.
“Can we increase gauge on the Monday flight (aka use a bigger plane)?” 

Hot Wire/Split 

A roundtrip from the hub (usually short) that straddles banks. There is a bank at 1030 and 1200 and 1530. This plane leaves at 1130 late out of the 1030 bank using a plane coming in early to the 1200 bank and gets back for the 1530 bank. Usually an Omni city. Hot Wire refers to a wiring diagram that looks similar to the appearance of this tactic on a bank structure schedule.
“The 1300 bank has a lot of hot wires”. 

Incremental Traffic 

If an airline has a 70% market share of El Paso – San Diego, but doesn’t fly the market non-stop because QSI analysis says that a non-stop flight would be full, but only increase share to 78%. Then even though the plane would be full the incremental traffic is only the increase of 8% in share, and thus not incrementally profitable.
“We could add another flight, but I’m not sure there is more incremental to get” 

Isolated Line/Broken Continuity 

This happens when there is not a fully rotating schedule. A group of planes are a single rotation group over some number of days that do not have a point to rotate with the rest of the fleet. Generally this is a bad thing that needs to be fixed.
“Your schedule has broken continuity on the A321s. The HSV RON is on an isolated line.” 

Leakage 

Passengers who drive to an airport that is not the closest option for them for lower fares or better service.
“It seems like ISP would do better, but they have a ton of leakage” 

Line/Line of Flight 

As shown on the Hangar Queen Report, it is one day of flying for a plane or crew.
“An A320 is on that line”. 

MCT Minimum Connect Time 

The least amount of time at a hub or connect point that a reservations system will allow connects to be built. If the MCT is 30 minutes then a connect with 29 minutes between flights cannot be purchased on a single ticket. MCT Exception There can be MCT exceptions for many things. Specific flight numbers, flights requiring CBP processing, flights on distant concourses, etc.
“Europe arrivals have a 75 minute MCT Exception” 

Minimum Turn Time 

Airlines use software to optimize schedules and generate Lines of Flight which allocate planes across the schedule. This software has a Minimum Turn Time for a particular fleet type set. For a CRJ it might be 25 minutes, but for a 777-300 it might be 90 minutes. It's the minimum amount of time to turn a plane from arrival to departure at gate. There are also exceptions for particular stations, maintenance requirements, international vs domestic, etc.
“The 737 MAX 8 has a minimum turn of 50 minutes at Chicago O'Hare.” 

O&T Originator and Terminator 

An airport where a plane ends and then begins its day. Like a RON.
“That station has an O&T.” The “O is pretty late in TUS.” “We need all Ts in by midnight”. 

Omni 

A bank or hub with no clear directional emphasis such as West to East.
“The 0730 originators are omni.” 

Out and Back 

A flight that leaves the hub, turns at the out station, and returns to the same hub. Out and backs increase schedule reliability, but usually hurt utilization or don’t work optimally with banking.
“Loads are poor on that out and back, drop it on Tuesdays.” 

The Pad 

Remote parking without a jetway.
“We are out of gates, it will have to go to the pad.” “The RONs on gate and 2 on pads/remote.” 

Pivot Point 

The maximum distance from a directionally banked hub where planes can turn and come back into a bank. There would normally be a pivot point on each side of the hub. There can be multiple pivot points if the hub has a lot of banks.
“The pivot is Miami so if we add Key West it won’t connect well.” 

QSI 

Quantitative Service Index is a process developed in the Civil Aeronautics Board (CAB) era for forecasting airline routes using a mathematical formula that assigns a numeric value to the quality of a flight or connect option based on quality factors like aircraft type, elapsed time, circuity, etc.
“QSI the new schedule and see if how we did” 

Rolling banks 

Very large banks and separation requirements eventually create a looser bank structure where flights depart more continuously. Rolling banks cut revenue through loss of connections, but may cut operating costs through reduced taxi time and fewer delays.
“We should look to see if DFW would work with rolling banks.” 

RON 

Overnight of a plane or crew.
“We have 3 RONs in BHM.” 

Round-Robin/Triangle Routing 

A routing that goes in a circle on a single flight number. For example, Charlotte-Ithaca-Elmira-Charlotte on a single flight number where passengers can buy Charlotte-Ithaca, Charlotte-Elmira as single plane service aka a 1-stop, Ithaca-Charlotte as single plane service aka a 1-stop, and Elmira-Charlotte. Tickets may or may not be sold for Ithaca-Elmira as a standalone route.
“U Air has a round-robin on Charlotte-Elmira-Ithaca.” 

S Curve 

The difference between Fair Share and Reality, or Share Gap, using QSI can often be predicted using an S Curve. An S Curve shows that carriers with a higher Fair Share overperform on QSI in most cases (all things being equal like legacy vs legacy), and a carrier with low Fair Share underperforms. Similar to "the rich get richer and the poor get poorer".
“According to the S Curve we should be doing better in LAX” 

Spill 

Boeing made a spill model long ago before revenue management existed. It predicts the amount of inherent demand a particular flown load factor implies. In essence, above 55% load factor or so, there were more people who wanted to fly than were accommodated. This happens because of price differences across fares (which became revenue management) and peaking on some flights. At a load factor of 95%, the amount of spill might have indicated a Demand Factor of 150-170%. This means that 45% of demand was not accommodated at a 95% load factor. Revenue management is essentially intentional spilling of the passengers willing to pay the least.
“The 1700 departure is heavily spilling can we get a bigger plane?” 

Stranded Crew 

A station only has one flight that is not daily and the roundtrip is over the maximum pilot duty day plus the RON is too short for a legal crew overnight. This would mean in most cases (certainly domestic) the crew is stranded for multiple overnights which is always avoided.
“There’s a stranded crew in ANC.” 

Tow Up 

A RON originator will be towed to the gate from the pad to depart.
“The 930 is a tow up.” 

Transition Schedule 

Crew is typically scheduled by the month or something akin to a month. Flight schedules often follow these timeframes or the IATA slot season. Joining one schedule to another is painful as they are often separate computer files and it can be difficult to make sure there is a plane in the right place for the new schedule. A poorly done transition schedule results in ferrying and perhaps somebody getting fired.
“Make sure the transition schedule is clean.” 

Wingtips 

Two nearly identically timed flights between the same two airports. These used to be very common before modern revenue management and were basically a way to either waste slots or get more capacity on very busy routes. Delta and US Airways used them commonly. For example, Washington National (DCA) had routine wingtips to Charlotte (CLT) and Pittsburgh (PIT) often with two flights departing DCA at something like 1700 and 1705. Often the time is slightly offset to reduce confusion. Best case the flights are on adjacent gates to minimize passenger issues.
"We don't have a widebody, so put A320 wingtips on the prime Atlanta - Chicago trip".