Originally Posted by polonius

They don't need to ask -- they will look at your PNR data. I have several times flown places on a one-way ticket, and it has generally resulted in extra questioning by immigration and usually in the need to prove I had enough funds to get home with. They knew this without having asked me.

Originally Posted by g7mcmug;

Yes, they might ask you why you have one way ticket, and the intent of the trip. They want to make sure you are not trying to smuggle into US and not going back to your home. Be expected to be asked lots of question by custom