FTers: FlyerTalkers -- all members who participate in FlyerTalk forums.
FWIW: "For What It's Worth"
G
GDS: "Global Distribution System" - Major CRS operation that books and sells tickets for airlines
H
HA: Hawaiian Airlines
HBA: Hobart airport
HH: Hilton Honors - the Hilton frequent stay program
HIP: Higher Intermediate Point
HLO: Hand Luggage Only (Preferred method of many Frequent Flyers)
HUACA: Hang Up and Call Again - If you're not getting what you want from a Telephone Agent, politely end the call and redial.
HVC: "High Value Customer" - Term used by ailines to indicate those they make the most nett revenue from.
I
I: Deep discount (heavily restricted) business booking class (see also J, D)
(NB: I represents other classes/ codes too e.g. *A business award & upgrade booking code)
IANAL: I am Not a Lawyer (Disclaimer, generally placed before "But, <legal stuff>"
IATA: International Air Transport Association
IB: Iberia
ICAO: International Civil Aviation Organisation
IFE: In Flight Entertainment (also AVOD IFE)
IHG: Intercontinental Hotels Group (See PC)
IIRC: "If I Recall Correctly"
ILS: Instrument Landing System (bad weather)
IME: In My Experience
IMO: "In My Opinion" or
IMHO -- "In My Humble/Honest Opinion"
INSPass: A pass allowing expedited passage - US Customs/ Immigration.
ISTR: "I seem to recall/remember"
IVML: Indian vegetarian meal
J
J: Full-fare Business booking class OR generic Business (see also D)
JASA: Qantas Frequent Flyer "Any Seat Award" in Business class (earns SC's)
JL: Japan Airlines
JQ: Jetstar
JQi: Jet Star International
K
KE: Korean Air
KL: KLM-Royal Dutch Airlines
KUPP: "Instant Upgrade" fare available in the USA. "Economy" fare that books into First/Business class. (See HUPP/YUPP)
KVML: Kosher vegetarian meal
L
LA: LATAM Airlines
LAG(
S): Liquid(s), Aerosol(s) and Gel(s) - Pertains to travel restrictions
LCC: Low Cost Carrier
LH: Lufthansa
LMAO: "Laughing My @rse Off"
LM: Lifemiles (Avianca Frequent Flyer Scheme [good for reasonable priced mile purchase for *A award redemptions])
LO: Lot Polish Airlines
LOL: "Laugh(ing) Out Loud"
LOTFAP: Land Of The Free And Paranoid a.k.a. The U.S.A.
LX: Swiss International Air Lines
LY: El Al Israel Airlines
M
MASA: Qantas term for Marginal Any Seat award (Includes JASA, FASA, WASA and YASA)
MCT: Minimum Connection Time
MEL: Melbourne airport
MH: Malaysia Airlines
MHC: Mile High Club
MPM: Maximum Permitted Mileage (e.g. RTW fares have MPM limits).