Re: While booking an international air-travel trip..
yes, you can…there is a link for FFP for every airline on their websites.
most airlines allow 6 months to collect points retroactively. one call to them can fetch you all the info you might need.
good luck.
btw, when you buy a ticket online from United Airlines, you can get a $50 credit on your first statement when you sign up for the credit card which has no annual fee and you can surrender anytime you want.
a few other airlines also offer this $50 credit.
it’s NOT available for Canadians with addresses in Canada. however, Canadians can use a relatives US address to get the credit.