The alert, issued ahead of the summer’s last busy travel weekend, said terrorists have considered renting private planes and loading them with explosives.

“Al-Qaida and its affiliates have maintained an interest in obtaining aviation training, particularly on small aircraft, and in recruiting Western individuals for training in Europe or the United States, although we do not have current, credible information or intelligence of an imminent attack being planned,” according to the bulletin obtained by The Associated Press.

The bulletin also says al-Qaida would like to use sympathetic Westerners to get flight training, then get them to become flight instructors.