AA is the only one that I'm aware of. Generally it's easier to maintain AA status after you've earned it once because the elite bonus applies to all OW flights and counts toward your total LPs. But have a look first at the airlines you usually fly and the actual fare class. There are some very notable economy fares that earn zero in AA (and many other OW programs) and can only earn anything in their native programs. CX and MH have the most that I'm aware of. Wheretocredit is a great source for this info. Just select the airline and the actual fare code you've been flying on to gauge how it will credit. You'd need to achieve 75k Loyalty Points per year to maintain Platinum in AA, which isn't particularly difficult if you embrace the Loyalty Point system. For flights, you'd take Base miles + Cabin bonus (if any, usually only for premium cabin), then add that to 60% of base (if Platinum). So a 1000 flight on an airline other than AA, BA, and IB - let's assume a 100% earning fare for simplicity would earn 1600 miles and LPs (1000 base and 600 elite bonus). AA and starting next week BA and IB are all based on revenue and you'd get 8 miles & points per pre-tax dollar of the ticket price, that might be good or bad depending on the ticket price your company is buying you.