Originally Posted by sailingfun

That is incorrect, I researched this quite a bit and spoke with tax professionals several years ago because I considered living outside the US for a bit. You are confusing state tax law. Federal tax law allows expatriate tax status only on income earned outside the US. A TWA pilot living in the Bahamas flying international took the issue all the way through the court system. The IRS maintained that you are taxed based on your domicile being the place of earnings. The IRS rule was backed by the court system. If you are based in NYC all income is considered earned in the US and you owe full income tax on that money.
If Delta opened a domicile overseas you could then legally claim to be a expatriate however its not likely at the moment we will see that happen. For the moment if your based in the US your taxed in the US regardless of where you reside or the type of flying you do.