America's Defense Officials in recent years have wanted to continue the use of blimps for airborne surveillance because they are inexpensive to operate and can operate aloft for long periods. The US Army, however, has confirmed it is ending blimp purchases because of budget cuts, including a seven-story blimp project by Northrop Grumman that cost more than $500 million.
UAVs can cost around $2.5 million each and are apparently still in surveillance favor, plus they can launch missiles and other ordnance.