U.S. National Guardsman from Roseburg, Oregon, Alek Skarlatos , left, waves to the media as he leaves the Elysee Place in Paris, France, with U.S. Airman Spencer Stone, after being awarded with the French Legion of Honor by French President, Francois Hollande, Monday, Aug. 24, 2015. (AP Photo/Michel Euler)

WASHINGTON –  Airman 1st Class Spencer Stone's military unit is nominating him for the prestigious Airman's Medal in honor of his actions to subdue a heavily armed gunman on the Amsterdam-to-Paris train last Friday, Air Force Secretary Deborah Lee James told reporters.

And Stone — whose nickname from his training days has been "Captain America" — could eventually be eligible for the Purple Heart, if French authorities conclude the attack was a terrorist event, according to Air Force Chief of Staff Gen. Mark A. Welsh.

Stone, U.S. Army Spec. Alek Skarlatos, their friend Anthony Sadler and British businessman Chris Norman, all jumped on the gunman as he moved through the train with an assault rifle strapped to his chest. The four received France's highest award, the Legion d'Honneur, on Monday.

"Had it not been for this heroic quartet, I'm quite sure that today we would be sitting here discussing a bloodbath instead of what, in fact, we are going to discuss," James said during a Pentagon press conference announcing the unit's award nomination. "Airman Stone and his friends personified service before self: no question about it. Their fearlessness, courage, and selflessness should inspire all of us, and thanks to them, no one died on that high-speed European train on Friday."

The Airman's Medal is the service's highest non-combat award, and is ranked above the Purple Heart. The medal is awarded to service members who commit a heroic act, "usually at the voluntary risk of his or her life but not involving actual combat," according to the Air Force description of the award.

James said she spoke to Stone and his mother, and was told that he is doing well, but needs some rest after the events of the last several days.