Wash. Rev. Code § 82.48.100
This chapter shall not apply to:
Aircraft owned by and used exclusively in the service of any government or any political subdivision thereof, including the government of the United States, any state, territory, or possession of the United States, or the District of Columbia, which are not engaged in carrying persons or property for commercial purposes;
Aircraft registered under the laws of a foreign country;
Aircraft which are owned by a nonresident and registered in another state: PROVIDED, That if any such aircraft shall remain in and/or be based in this state for a period of ninety days or longer it shall not be exempt under this section;
Aircraft engaged principally in commercial flying which constitutes interstate or foreign commerce; and aircraft owned by the manufacturer thereof while being operated for test or experimental purposes, or for the purpose of training crews for purchasers of the aircraft;
Aircraft being held for sale, exchange, delivery, test, or demonstration purposes solely as stock in trade of an aircraft dealer licensed under Title 14 RCW;
Aircraft owned by a nonresident of this state if the aircraft is kept at an airport in this state and that airport is jointly owned or operated by a municipal corporation or other governmental entity of this state and a municipal corporation or other governmental entity of another state, and the owner or operator of the aircraft provides the department with proof that the owner or operator has paid all taxes, license fees, and registration fees required by the state in which the owner or operator resides.
RCW 82.48.100
Effective date-1965 ex.s. c 173: See note following RCW 82.04.050.