Lisbon is Portugal's capital and one of many European' hub airports. The city airport is excellent for travellers as it is only 10 minutes away from the city centre! In fact no other capital in Europe can benefit from low cost flights to its main airport!
Many airlines, including low-cost, operate more than one daily flight to Portugal. There are plenty flight connections from almost all countries in Europe to Faro, Lisbon or Porto airports.
The islands of Madeira and Azores also have regular flights between Europe and USA. Check out some of the flight companies flying to Portugal: