Originally Posted by
cookielb
(I do understand that she will have to pay money later to transfer the miles over to her AA account, but depending on the mileage difference, it may be worth it)
You cannot transfer miles from a BA account to an AA account or vice-versa.
Originally Posted by
cookielb
Also, she will be traveling with her daughter that is under 18- will they be able to collect her daughter's miles despite the age constraints?
There are (generally) no age constraints on frequent flyer accounts. The daughter needs her own account (either AA or BA).
Does your boss have status on AA? Most people concentrate their mileage-earning with one airline, so as to achieve status on that airline (which status generally carries over to (i.e., is recognized by) other oneworld airlines (so status on AA is recognized by BA for purposes of lounge admission, advance seating etc.). Very few people fly enough to make it worthwhile to split their miles between two different airlines (particularly as there is no way to combine those miles or transfer them when it comes to using them for awards).