You do understand that there are classified Executive Orders, right? There have been several signed, including some publicly admitted too (but not the contents of the orders themselves).
The requirement to show ID at airports (Before 9/11) was, I believe, the result of a classified Executive Order. This is an
older Slate article (yeah, it's slate, but the info verifies elsewhere):
Former Rep. Helen Chenoweth-Hage, R-Idaho, experienced the existential horror of being governed by secret laws last month while attempting to board a United Airlines flight from Boise to Reno. When pulled aside by security guards from the Transportation Security Administration for additional screening, including a physical pat-down, Chenoweth-Hage requested a copy of the federal regulation authorizing such searches. Her request was denied.
Upon reading the article - I'm wrong about the ID thing being an "executive order", it's a "sensitive security information" thing that came about in 1974 with the the Air Transportation Safety Act.