There was a campaign to stop the auction, but Germany is not subject to U.S. laws.
The German lawmakers have requested information from the Kusel-Landstuhl tax office and expect a response later this month.
Federal prosecutors said the suspects were arrested by tactical police units early Wednesday.
Preparations in Germany follow facility closures at the base in Vicenza, Italy.
Brig. Gen. Ronald Stephens, who leads Regional Health Command-Europe, was suspended Feb. 12, USAREUR said in a statement.
Germany said Tuesday it is abandoning plans to install a new airborne reconnaissance system on U.S.-made drones.
Germany resumed training in Irbil on Sunday morning together with its partners.
Americans assigned to Air Force bases in Europe could soon be paying higher rents for off-base homes.
The Allies and former enemy Germany together marked the 75th anniversary of one of the most important battles in WWII.
It's not clear what unit the alleged fare-dodgers hailed from.