For most US positions, just Permanent Residency will do. Of course, if you are married to a US Citizen, you would still need to apply for this.
There are a few jobs that require citizenship, because they are usually governmental or require a security clearance because they are involved in military contracts. However, they are not the usual airlines, and besides, would you really want to have that on your conscience, basically screwing small countries while serving as a henchman of Corporate America's black hand in the name of "national security"?
