Be highly aware of germs transmitted through shared surfaces, or those places that are constantly touched by many.
If you couldn't avoid touching those surfaces, be sure to wash your hands frequently, use a sanitizer and/or clean any surfaces with a disinfectant wipe. Also, be sure you drink plenty of water and be well-rested.
If you're in a plane, don't think it is the air quality or cabin air because it is mostly well circulated and filtered.
So, just keep enjoying your air travel ;)