The main point of this paper is that rear area bases are too vulnerable now. This paper is from West Point, and is the view from the Army side. It's a big problem for air forces, too.

The US has a tradition of large, supposedly secure bases in the rear. The USAF has relied on this since WWII. It's not working any more. Iran has been hitting US air bases. In the last day, they've hit US bases in Qatar, Jordan, Kuwait and Bahrain. That's just this round. There were previous hits a few months back. It's not publicized much, but it's no secret. It's hard to protect an air base against drones. Air bases are big, everyone knows where they are, airplanes are hard to hide from drones, and are vulnerable to small explosive charges. As Russia keeps finding out as Ukraine hits their air bases. There have been hits well inside Russia. Blast-resistant hangars in Crimea have been attacked. Don't leave a door open.

China is going in for airbase hardening in a big way.[1] This is sometimes called a "concrete sky" program. The USAF is way behind in the Pacific. Too many planes parked out in the open, or in weak hangars.

Active defenses against drones and missiles do work, but they just thin them out. Some get through. If the attacker has enough manufacturing capacity, the defenses can be overwhelmed. Ukraine is currently building about 7 million drones a year.

[1] https://www.hudson.org/arms-control-nonproliferation/concret...