You cannot fly anywhere in possession of marijuana. All commercial airports and airlines are under Federal jurisdiction. Federal law does not recognize marijuana legalization on the state level. Once you enter an airport, whether you are flying or not, it is illegal to possess marijuana. The TSA might let you go with warning or they could hand you over to authorities for prosecution.
Yes thanks to a new law from 2015 you are now allowed to fly with marijuana if you have a medical marijuana card. Just make sure to bring all of your documentation with you so that there are no problems at the airport. If you have that then everything should be smooth from there.
The issue of whether you can travel on airplanes with marijuana is complicated by the fact that TSA agents are federal government agents, and marijuana is still illegal on the federal level. Crossing state lines with marijuana is still a crime, even if you start off in Oregon. Theoretically speaking, if you fly in-state, you should be able to carry your recreational marijuana on the airplane, but do not be surprised if you are questioned by a TSA agent if they find it in your luggage.