Car2Go agreement with Montreal's Trudeau Airport could be a model for other jurisdictions
The Airport has an agreement with an off-site parking lot that allows Car2Go vehicles to be parked there. A $7.50 parking fee upcharge is charged to the user. The Airport covers extra costs if more than ten cars are parked at the AéroParc lot, which is the number of spaces that has been contracted for normally. See "Car2Go users can park at the Trudeau airport" from the Montreal Gazette.
Note that US members of Car2Go have full access to cars in all US and Canadian cities that participate in the Car2Go program. (In other news, in some cities in parts of the city where Car2Go is less successful, they are cutting back on the size of the home service area. See "Car2Go proposes scaling back service area in Twin Cities" from the Minneapolis Star-Tribune.)
Given the large capacity for parking at National Airport's various parking garages and lots, it seems like something could be worked with regard to access to DC Car2Go members.
DCA has about 10,000 on-site parking spaces, so they could spare 10-20 spaces for Car2Go use--especially if they think about this in terms of "managing the quality of the passenger experience" at more touchpoints than they normally consider.