I don't know if it's a majority, it may be, but it's at least a large minority.
Airlines (both passenger and freight) don't want to pay to train their own pilots, so their staffing pipelines rely heavily on ex-military pilots.
Many military and passenger aircraft share a basic airframe, for example the KC-135 is a 707 configured as a tanker for aerial refueling. Even the instances that are not - it would be relatively straightforward to transition from, say, a C-17 to a 767 or something like that.
So pilots tend to retire from the USAF and fly the friendly skies with civilian airliners.
Airlines (both passenger and freight) don't want to pay to train their own pilots, so their staffing pipelines rely heavily on ex-military pilots.
Many military and passenger aircraft share a basic airframe, for example the KC-135 is a 707 configured as a tanker for aerial refueling. Even the instances that are not - it would be relatively straightforward to transition from, say, a C-17 to a 767 or something like that.
So pilots tend to retire from the USAF and fly the friendly skies with civilian airliners.