The downing of Egyptair Flight MS804 raises questions about the adequacy of airport security.  Over the past week American news outlets have been reporting stories of airport security lines 2-3 hours long, with warnings that those lines could get even longer as the high season of summer travel gets underway.

In part, these long waits are due to inefficiencies and misspending by the TSA, according to Chris Edwards from the Cato Institute.  In part the waits are also due to heightened efforts to keep U.S. air travel safe from passengers who are would-be attackers.

But there is evidence that the real threat may not come from those waiting in line, but from those behind the line, from airport employees.

A trial is currently underway in Minneapolis, Minnesota, for three of ten Somali-Americans who aspired to fight with ISIS.  Of the three, two were recently employed by the Minneapolis-St. Paul International Airport.  Indeed the “emir” of the group, Abdulrizik Warsame, was a cargo and baggage handler and bragged about being able to blow up a plane.

In the wake of the attack at the Brussels-Zaventem Airport on March 22, which killed dozens of people, members of the police union in Brussels alleged that as many as 50 ISIS supporters may have been working at the airport as cleaners, caterers, and baggage handlers.  ISIS itself has claimed it has terror cells in airports around the world.

Here in the United States, The Department of Homeland Security has said that only three airports in the United States out of a total of 450 regularly require employees to pass through security screening.  According to Fox 25’s Washington Bureau, 73 airport employees had been flagged by the Homeland Security Inspector General for ties to terror.

In addition to concerns about inadequate screening of airport employees, questions have also been raised about the Obama administration’s handling of terrorism cases.

Scott W. Johnson has written that Abdirizak Warsame, the ringleader of the Minnesota 10 who pled guilty to supporting ISIS, will be the beneficiary of an experimental “Terrorism Disengagement and Deradicalization Program.”

This comes on the heels of the Obama administration’s shifting of resources away from traditional counter-terrorism efforts such as training of law enforcement and into “Countering Violent Extremism” (or CVE) programs.

The shift to CVE is problematic for three reasons: it means a reliance on programs and methods that are unproven and experimental. It means a reliance on the Muslim community to more fully cooperate with law enforcement.  However, of the currently 100 ISIS supporters in the United States who have been interdicted by law enforcement since March 2014, not a single one was turned in by a “Muslim leader.”  And third, it has pulled resources away from training for federal, state, and local law enforcement, leaving them underprepared for the current threat.

While it may be some time before a clear chain of events is established for the Egyptair flight that went down today, if it turns out that an airport employee in Paris was one link in the chain, it should cause a wide-scale rethinking of airport security in the United States.

Katharine C. Gorka is the president of the Council on Global Security.  @katharinegorka