Many programs allow you to upgrade or downgrade your plane's size, so if you need a longer-range plane or need more space, you can upgrade. If you are traveling alone on a short flight, you can downgrade. There are sometimes additional interchange fees for upgrading or downgrading, so if you expect to be doing a lot of either, it pays to pay attention to these fees and policies. Policies for upgrading, downgrading, and interchange fees are included in the Private Jet Card Comparisons' comparisons spreadsheet.