|Quoting EMBQA (Reply 2):|
You need to be a US Citizen for main line.......... but if you work for one of the Canadian feeder airlines, you should be fine.but then you should actually TRY the FedEx web site........ it WILL answer all your questions.
If you are working in the US, you must be either a citizen or have the appropriate visa. For years, many Canadians just came across the border and got a job. That is no longer possible as the employer has to check your documentation. As for flying in the US, you need a FAA license if you are flying for a US registered airline. Assuming you have a license (I would guess commerical should be enough), the appropriate type ratings, and such and a proper visa you should be able to work at any airline willing to give you a job. Now whether FedEx requires US citizenship, I don't know, but I doubt it. There is a pilot shortage, you know.
One issue may be the requirement for a US security clearance. That has nothing to do with the FAA, but FED EX
You can see more about the requirements here