They aren't taking them out of the sky. Let's just say Ansarallah are directly responsible for their destruction.

No they're not getting shot down directly, because Ansarallah/the Houthis have never claimed a shoot down during their public statements (while they are very quick to claim the shootdown of MQ-9 Reaper drones for instance), Yemen don't have the systems to shoot down aircraft hundreds of kilometres out at sea where the losses take place, and there's been no evidence presented of manned US aircraft going down over Yemeni soil, no wreckage, no ejections over Yemen, no search and rescue missions for the pilots, no pilots captured by the Yemeni Armed Forces.

However, the F-18 losses are still a result of Ansarallah/Houthi attacks on the aircraft carrier. So still as a result of Ansarallah/Houthi attacks, even though they're not being shot down directly. As for the three F-18s lost by the USS Harry Truman aircraft carrier during it's 7½ month deployment, here's a breakdown:

• First during a friendly fire incident: F-18 in mid air refueling configuration (F-18s can refuel other F-18s) went out to hunt a drone, upon returning to its regular flight path, an air defence operator on the USS Gettysburg lit it up with an SM-2 thinking it was the drone.

• Second fell out of the hangar bay with tow truck attached during evasive maneuvers, during an Anti Ship Ballistic Missile (ASBM) attack.

• Third had an arrestor hook malfunction, while trying to land during an ASBM attack.

Considering the military generally recruits people who have nothing else going for them, I can imagine they just keep forgetting to put the planes in park

Yeah, it's one thing to lose a single plane to an accident. But 3? No way.

they were under ASBM attack at the time, causing things to get hectic and the carrier to be doing evasive maneuvers

It's a long deployment and much more active than they usually are. They're likely getting fatigued and overlooking things.