Drive to the airport. Park. Open the trunk. Remove the bags. Go into airport with bags. Give him his plane ticket. He'll get the hint eventually. The hard part is seeming absolutely normal until you drive into the airport.
Seriously, my Dad did this to my Mom for their 30th wedding anniversary. They retraced their honeymoon from 1959. By 1989, the roads had improved and Chattanooga Tn, was only a 3 1/2 hour drive from their home. Dad told Mom that they were running an errand to Huntsville, Al., and by the time Mom figured it out, they were over half way there. She was thrilled to see that her bags were packed and she was all set. By all accounts they had a wonderful time. I was just happy to be in on the decoy of a cake and ice cream party before they left. I'm so glad that it was a magical trip for them. Mom died unexpectadly soon after their 32nd anniversary, so its a really happy memory for the rest of us.
