Some of my buddy's are foreign national and even flying for an airline they were furloughed pending the review of their background check .
One applied to a regional , and he was told that there would be indefinite delays before they get to him, the other one just became a US citizen and was given a class date.
Where I work and as well as about every airlines , Citizen will be hired first , there is too many pilots unemployed at this time , the ambiance in the cockpit is not always very friendly if you are seating next to an air force or navy guy, I reccomend to confront him immediately if he start to argue about foreigners at least that"s how I got rid of the problem .