Interestingly, at least some of these flights are not listed in the timetable. For example, AC 5358 (ORD-LHR) isn't listed there. This makes my problem harder, because I don't care very much where I fly from or to as long as the flights have AC flight numbers and take place on United aircraft. I want to try to string together a series of such flights such that I get as many miles as possible within the constraints of my $3200 credit. For this reason, I really want to be able to see all available flights rather than choosing specific cities to fly between.