One active soldier and several reservists are among those being investigated, a spokesperson for the military intelligence service (BAMAD) told Reuters.
The incident occurred while passengers were boarding a flight between Seattle, Washington to Dallas-Fort Worth, Texas.
According to the organization, this legislation was brought forward as a result of two cultural centers in Bulgaria that was named for Bulgarian Nazi collaborators.
This behavior was specifically targeted at the field during the "Welcome to Country" ceremony at the beginning of the game.
A Goodwill online store put on their site a trio Nazi memorabilia mugs listing them as "3 Vintage Adolf Hitler German Mugs with Pin."
This call to action comes as jury trials are beginning for Patriot Front members accused of conspiring to riot at an LGBTQ pride event in downtown Couer d'Alene, Idaho, in June.
Belgium has not yet made it illegal to have Nazi symbols up in public places, or even on license plates.
James Owens concealed hate speech about Jewish people on his YouTube channel, using terms such as "people who look white but aren't" and referring to Hitler as "our uncle."
This is the latest in a string of antisemitic flyer distribution incidents across the US, raising concerns in Jewish organizations.
In a video that has since gone viral, pop singer Justin Bieber appears to perform the Nazi salute and march onstage in a show in Finland.