British Airways is currently offering very cheap open-jaw flights from Europe to USA. You can get flights from Oslo/Luxembourg/Brussels to New York and back from Washington/Philadelphia/Baltimore to Germany or Austria from only 234 EUR.
January – March 2015
50 EURO more in the summer
Luxemburg – New York and Washington – Düsseldorf
Luxemburg – New York and Philadelphia – Düsseldorf
Oslo – New York and Washington – Berlin
How to book:
Between New York and Philadelphia, Washington you can travel by MegaBus.com (prices start from 1 USD + tax).
Baggage during the trip:
One cabin bag and one checked in baggage per passenger.