LMMFAO
"In recent years, new commercial aircraft have been designed to recirculate approximately 50% of the cabin air to increase fuel efficiency..."
https://www.ncbi.nlm.nih.gov/pubmed/12132979
Roll around together. Make out madly. Passionate frottage front-to-front. Stick your fingers up each others' butt. Suck each other off. Mutual mast. Etc.!
Free your mind...!