ORLANDO, Fla. — Three People’s Liberation Army Air Force officers crashed a U.S. Air Force conference here this week, raising eyebrows from military officers and defense executives alike.

A senior U.S. military official and two defense executives confirmed the presence of the Chinese officers who were in uniform Thursday but in plain clothes Friday.

The trio walked around the large exposition hall at the conference hotel near Disney World snapping pictures of military gear and models of drones and other aircraft, some of the military’s most advanced weapons.

While no classified information is on display, defense firms oftentimes show off their latest prototypes and most advanced military equipment. This year, Boeing featured a new helicopter it wants the Air Force to buy to guard its nuclear missile fields, Northrop Grumman had a model of a new ICBM, and Lockheed Martin and Raytheon showed off models of new aircraft missiles.

Firms sometimes display more sensitive or proprietary technology inside of trailers or secure conference rooms guided by security officers.

One American executive said that the Chinese officers inquired about the specifics of one of the company’s communication systems. The American official did not provide any details.

This week’s Air Warfare Symposium — hosted by the Air Force Association — is open to the public. A ticket costs $1,025, plus an additional $180 to attend a welcome reception widely attended by senior military officials and defense executives.

It’s not uncommon for foreign military officers to attend trade shows like the one here this week. However, the ones that do attend are usually from American allies. Uniformed Chinese and Russian military officers are more commonplace at arms shows in the Middle East.

Military officials and defense executives say it's common for foreign officials to approach them at trade shows, like the one here this week. The key, they say, is to be polite, but disclose nothing.