I didn't know where else to post this because it's really general question about any (domestic) carrier's FF program.

If I am booking a trip to, say, Hawaii, for myself, spouse and 2 children - can I accrue all of the miles onto my single FF account - or do I need to create accounts for my children? What about my spouse? Is there a way to combine those miles back into a single account? What is the fee (generally) for combining miles?

It seems silly that if I am the sole purchaser of X number of tickets for me and my family that those mile would have to be distributed to those family members that are flying and not the person paying for those miles; but I understand that this is the case. Is this true for all (U.S.) domestic carriers?

Lisa