| Term |
Definition |
| M |
Booking class - use varies depending upon airline |
| M&M |
Miles & More (Lufthansa Group FFP - more commonly known at M&L - Miles & Less! |
| Mag |
Magnetometer, more accurately known as a Walk-Through Metal Detector |
| Mainline |
A reference to aircraft run by United proper rather than the commuter lines. Generally the larger multi-class planes. |
| Matron |
Airline employee, often middle-aged woman, who polices access to business and first class lounges. |
| Mattress Run |
The practice of checking into a hotel or a series of hotels, just to earn status credits and/or points in that hotel chain's frequent lodger program |
| MCE |
Main Cabin Extra (coming soon) some coach rows with extra legroom, sold for an extra fee or allocated to Elites |
| MCLA |
Mexico, Caribbean and Latin America |
| MCO |
Miscellaneous Charges Order, paper issued by the airline for a ticket refund, etc. Not to be confused with MCO, the code for |
| MCT |
Minimum Connection Time |
| MD or Mad Dog |
McDonnell Douglas 88 or 90 |
| MDD |
Modified Double Dip. A method of opening Sapphire Reserve and Sapphire Preferred in quick succession to bypass the Chase rule which does not allow holders of any Sapphire card to open another |
| Medallion Qualification Mile |
A unit of measurement used towards the qualification of elite Medallion status for the next year, earned only by actually being a passenger on an aircraft operated by Delta Air Lines or its partners, by using an approved credit card, or by special promotions. |
| Medallion Qualification Segment |
A unit of measurement used towards the qualification of elite Medallion status for the next year, earned only by actually being a passenger on an aircraft operated by Delta Air Lines or its partners. |
| MEL |
Minimum Equipment List (list of equipment allowed inoperative not affecting flight safety) |
| MEMBERSHIP PRIVILEGES |
Special privileges granted by airlines and hotels to members of frequent travel programs. For example, hotels may offer discounted rates or free nights to program members for a limited time. |
| METAL |
Refers to aircraft (thus metal) of the airline you are flying. (i.e., Delta metal, American metal, etc...). |
| MFU |
Miles For Upgrade (now referred to as Upgrade Using Avios) |
| MH |
Malaysia Airlines |
| MHC |
Mile High Club |
| MHD |
Mexican Hat Dance, a type of mileage run between Canada and Mexico |
| MIB |
Merchandise in Baggage |
| Midcon |
Flight that flies mid-continent, e.g. ORD-JFK or DFW-LAX |
| MIL |
Military Passenger |
| MILEAGE JUNKIE |
A frequent flyer who obsessively accumulates miles and points, and often does not redeem many awards. |
| MILEAGE MANIAC |
See MILEAGE JUNKIE. |
| MILEAGE PURCHASE |
The capability to purchase a certain percentage of miles needed to redeem a specific award. |
| MILEAGE RUN |
A series of flights taken in a very short amount of time, solely for the purpose of accumulating frequent flyer miles, with a blatant disregard for the destinations. |
| Million Miler |
A person who has earned a minimum of 1,000,000 Medallion Qualification Miles. |
| MINIMUM MILEAGE |
Minimum number of miles earned by a program member, regardless of the length of the flight; usually 500 miles. |
| MLL |
Maple Leaf Lounge - Air Canada's network of Elite and VIP airport lounges. |
| MM |
Million Mile Fliers- Not a bona-fide status level. Folks who fly 1,000,000 BIS miles are given permanent 1P status without need to qualify. |
| MMB |
Manage My Booking |
| MMW |
Millimeter Wave portal (aka "electronic strip-search machine") |
| Moat |
Nickname for Security Checkpoint |
| Moat Dragon |
A TSO manning a WTMD, MMW or BSX machine. |
| MOL |
Michael O'Leary |
| MOML |
Moslem Meal / Halal Meal (not available on all flights) |
| MP |
Mileage Plus - United's name for their frequent flyer program |
| MP |
MoneyPak |
| MPM |
Maximum Permitted Mileage. Many tickets especially RTW have a maximum number of miles permitted under the fare. |
| MQD |
Medallian Qualifying Dollars; Delta lingo for minimum spend |
| MQM |
Medallion Qualifier Miles, miles that count towards achievement of Elite status on Delta |
| MQS |
Medallion Qualification Segments, used to determine your qualification for elite status |
| MR |
Marriott Rewards |
| MR |
Mileage Run - A series of flights taken in a very short amount of time, solely for the purpose of accumulating frequent flyer miles, with a blatant disregard for the destinations. |
| MR |
is also used as an abbreviation for American Express Membership Rewards. |
| Mr. Easy Chicken, Easy Chicken, Mr. Chicken |
Various terms for the Easy Check-in kiosks in airports. |
| Mr. Pillows |
A character in a story of unknown veracity who has a seemingly endless supply of pillows available on UA. |
| MRO |
Maintenance, Repair & Overhaul |
| MRTC |
American's "More Room Throughout Coach" |
| MS |
Manufactured Spending |
| MS |
Egyptair |
| MSC |
Most Significant Carrier (important for baggage and some ticket issues) |
| MTEU |
Miles Towards Elite Upgrades (for earning 500 mile upgrades, etc.) |
| MTOW |
Maximum Take Off Weight (aircraft) |
| MU |
China Eastern Airlines |
| MUA |
Mileage Upgrade Award (an upgrade award using miles) |
| MX |
Maintenance |
| MX |
Mexicana de Aviacion OR flight canceled/delayed due to mechanical problems |
