The Corvallis area is served by the Portland International Airport (PDX) and by the Eugene Regional Airport (EUG).

PDX

The Portland airport has a direct flight to/from Amsterdam, seasonal flights to/from Frankfurt and London, and a direct flight to/from Tokyo. It is served by all major US carriers.
The HUT shuttle serves Corvallis every two hours (the journey takes approx 2.5 hours and all buses are equipped with WiFi). Alternatively, all major rental car companies are available from PDX. It's a 100 miles drive to Corvallis that takes approximately 1 hour and 45 minutes.

EUG

The Eugene airport is a regional airport served by all major US carriers. Shared van service Omni Shuttle is available from the airport to Corvallis. Al major rental car companies are available from EUG. It's a 36 miles drive to Corvallis that takes approximately 50 minutes.