Can you fly from Portland to Reno with a warrant in Washington?

Unless you are a "hunted" felon wanted for a SERIOUS crime then air travel is low risk when you have a warrant(s). There is no connection between airlines booking and check-in computers and state level law enforcement. You would have to be "recognized" by face. HOWEVER, some well funded agencies do constantly check flights, especially when they have tips and will be waiting to catch someone .... but in all honesty, the cops in Reno are not interested in arresting someone with a warrant in another state due to the cost of housing, extradition, etc.

Cobb County Georgia is notorious for going to great lengths and distances to extradite fugitives and still owes the city of Maui, Hawaii thousands of dollars for holding someone for 4 months until a deputy could fly out and bring them back. By the way, he was wanted for multiple DUI's.