Flying with a 6 week old

Stella2008

We are flying out to visit my IL's later this week...DH's parents are much older and cannot travel to see us, so we are going to them. With my first, we did not take her on an airplane until she was 2 (she did great on both flights) and so it was a much different experience than what I'll have with our newborn. 

Has anyone flown with their newborn? Any tips I should be aware of? Since it will be me, DH, 2 1/2 year old and 6 week old baby, my plan is to try and hijack a row of seats--DD #1 will be in her carseat by the window, DH and I will take turns wearing DD#2 in the Ergo. Thoughts?