As far as the immigration goes I have some experience, I used to have a green card but now posess a US passport. While it is technically possible to be sponsored for a work visa (H-type) as a pilot it is very unlikley the best way is to work for the same company abroad and then get an internal company transfer to a US base which would include the H-? Visa. Alternativley you could immigrate to the US in another profession and as soon as able apply for a change of status with the INS this is effectivley a green card application, it takes a few years but can be done. At the moment a possibility exists to get sponsored as a flight instructor. After two years you can apply for the adjustment of status and two years or so later your green(actually pink) card will arrive.