Start here: airline miles

What a mile is, and is not

A mileage account is personal and single. American limits each eligible individual to one AAdvantage membership and says rewards are for personal benefit and use, cannot be sold or bartered, and are not transferable except through the transfer routes it permits. [1] KrisFlyer states that membership is strictly personal, cannot be transferred, sold or bartered, and that pooling of miles or status credits is not allowed. [4]

Both programmes refuse double credit. American says the same flight, hotel stay or car rental cannot earn under AAdvantage and another loyalty programme, and that once a flight has departed the programme selection for it cannot be changed. [1] KrisFlyer allows credit with only one programme per flight or transaction and forfeits the credit where a member tries to accrue twice. [4] That makes the choice of programme a booking-time decision; the overview at what is a frequent flyer programme explains the structure you are choosing between.

Three ways of earning

American prices the ticket. Eligible purchased tickets normally earn Base Miles, which also earn Loyalty Points, on the ticket price — base fare plus mandatory carrier-imposed fees — excluding government taxes and optional airline fees such as change and ticketing fees. [1] Some partner-marketed flights, and fares whose actual amount is not disclosed, earn instead on a percentage of distance flown set by the booking code. [1] Certain fares are ineligible altogether, and flights to and from Cuba earn only on American-operated flights. [1]

Delta prices the dollar. Delta's earning page quotes 5 miles per US$1 in Classic or Refundable and 7 miles in Extra on Delta-marketed flights, 2 miles on Delta Basic, and no miles on Main Basic. [2] The eligible price is base fare plus carrier-imposed surcharges, excluding government taxes and fees, and miles go to the member flying regardless of who paid. [2]

KrisFlyer pays on distance. Miles are awarded on actual distance travelled by great circle between departure and arrival airports, plus bonuses where applicable, calculated sector by sector on connections that change flight number. [4] The share of that distance credited depends on cabin and booking class: 200% in Suites and First, 150% or 125% in Business, 125% or 100% in Premium Economy, and 100%, 75% or 50% in Economy. [4] No miles are earned on award or redemption tickets, infant fares, industry or agency discounts, charter flights, or codeshares marketed by Singapore Airlines and operated by a non-KrisFlyer partner. [4] The full menu of ground earning is covered in how to earn miles.

Ground spending often behaves differently from flying. At American, miles from Buy, Gift and Transfer transactions, from offers, and from converting another programme's currency are Bonus Miles only and earn no Loyalty Points. [1] Delta credits 2 miles per US$1 on stays and car rentals booked through Delta, and up to 10,000 bonus miles per Delta Vacations package, but says those bonus miles do not count toward Medallion qualification or Million Miler status. [2] Missing credit has a deadline: American accepts claims up to 12 months after the activity date, with shorter limits for travel before enrolment. [1] KrisFlyer asks members to wait two weeks for its own flights and four weeks for partner flights, then claim within six months of the transaction date. [4]

Spending miles

American's flight awards are one-way unless noted, allow at most three segments per one-way award inside the United States or Canada and four for other destinations, and must be completed within one year of ticketing. [1] The traveller's name must be given at ticketing, because the recipient cannot be identified later. [1] A wholly unused award cancelled before departure is reinstated provided the ticket has not expired; expired tickets and partially used awards are not. [1] American also warns that an award may be withdrawn or require more miles at any time before ticketing. [1]

KrisFlyer lists award and upgrade tickets on Singapore Airlines, Star Alliance and other partners, part or full payment of Singapore Airlines fares and taxes bought on singaporeair.com, KrisShop and KrisFlyer vRooms purchases, and conversion to partner programme points, among other uses. [4] A minimum of 1,500 miles applies per vRooms transaction. [4] Miles cannot pay for tickets bought through travel agents or ticket offices, for corporate or group fares, or for itineraries containing a segment not operated by Singapore Airlines, and conversions out of KrisFlyer cannot be reversed. [4] Work through the mechanics slowly with first award flight step by step, and see how to redeem miles for the wider picture.

Status runs on a second counter

AAdvantage tier qualification uses Loyalty Points earned in a 12-month period beginning each 1 March, and status then runs from the moment it is reached until 31 March of the following full year. [1] Because only Base Miles generate Loyalty Points, buying, gifting, transferring or converting miles raises the balance without moving tier progress. [1] Delta instead lifts the per-dollar rate for its own tiers: 7 miles per US$1 for Silver, 8 for Gold, 9 for Platinum and 11 for Diamond, against 5 or 7 for general members depending on fare type. [2]

The British Airways Club keeps tier points apart from miles: tier points are earned on eligible spend, meaning fare plus carrier-imposed charges but not airport or government taxes, plus a fixed number of extra tier points per flight based on haul, cabin and fare type. [3] From 1 April 2026, add-ons such as bags and seating earn tier points, and Sustainable Aviation Fuel contributions are capped at 2,000 tier points per membership year. [3] Reward Flights earn no tier points, though eligible add-ons to a Reward Flight do, and part-paying with Avios does not reduce the tier points on the original fare. [3] British Airways flights usually credit within three days, partner flights within seven, and British Airways Holidays packages within 14 days of the trip's end. [3]

KrisFlyer separates Elite miles from redeemable miles: Elite miles decide Elite Silver and Elite Gold, cannot be spent, and reset to zero at the end of each membership year. [4] PPS Value is earned only on Suites, First and Business tickets, not on Premium Economy or Economy. [4] Since 1 September 2025, spending through Kris+, KrisShop and Pelago also earns non-flight Elite miles, capped at 5,000 for Elite Silver and 10,000 for Elite Gold. [4] For the vocabulary of tiers, see elite status, and for the airline groupings that feed partner earning see airline alliances explained.

Exceptions and limits

• Not every flight earns. American excludes certain fares; Delta excludes Main Basic tickets; KrisFlyer excludes award tickets, infant fares, charter flights and some codeshares. [1] [2] [4]
• Inactivity can close an account. American may terminate an account when 36 consecutive months pass without earning or redeeming activity, together with a zero balance, no co-branded card and no lifetime benefit or active status; accounts opened within the previous 24 months can be terminated after 12 months of no activity. [1] KrisFlyer may close an account after 45 months with no recorded activity, measured as earning miles, or after 24 months from joining. [4]
• The terms can change. American reserves the right to change programme rules even where the change affects the value of rewards already accumulated, Delta may change SkyMiles rules at any time with or without notice, and Singapore Airlines reserves the right to modify KrisFlyer without prior notice. [1] [2] [4]
• Dates matter. The AAdvantage terms used here are dated 13 January 2026 and effective 1 March 2026; British Airways extra tier points and the 2-tier-point rate on add-ons apply from 1 April 2026, while several partner tables on the same page take effect from 1 April 2025. [1] [3]

Related pages

Start with what is a frequent flyer programme, then decide where to credit flights with choose your main programme. Earning and spending are covered in how to earn miles and how to redeem miles, with the practical walkthrough in first award flight step by step. Background: airline alliances explained, elite status and the glossary.

Sources

Sources checked on 18 October 2026. Only the four programme pages below were used: American's terms cover AAdvantage earning, redemption and status; Delta's page covers SkyMiles earning; the British Airways page used here covers tier points on flights, not Avios earning or spending rates; Singapore Airlines' page covers KrisFlyer terms. Other programmes, including United MileagePlus, Flying Blue, Aeroplan, Emirates Skywards and Asia Miles, and alliance-level rules, are not covered here.

1. AAdvantage terms and conditions (American Airlines), checked 18 October 2026
2. How to earn miles (Delta SkyMiles), checked 18 October 2026
3. Earning tier points on flights (The British Airways Club), checked 18 October 2026
4. KrisFlyer terms and conditions (Singapore Airlines), checked 18 October 2026