Customs & Border Patrol. Immigration and Customs Enforcement. Domestic travel does not involve immigration or customs. No international borders are crossed.
Giving CBP line-item access to the movements of Americans makes as much sense as giving the SEC access to healthcare records.
There is virtually no reason at all for these organizations to have any knowledge about the movements of people inside the US. They do not get to be super-police just because they want to be.
I happen to believe that this is all just a convoluted way to back into the fuhrerprinzip by way of originalism, but I have no power.
Either way, the US is not a liberal democracy any more. Laws do not apply to the powerful. Strength and power are the only things that matter. The Enlightment project is dead in Washington (and most statehouses) and the only question of consequence left is: What will replace it?
All of the things that were perfectly OK for Trump to do will suddenly be off limits for a Democrat president.
Why are the misdemeanor civil violators ICE chases so important that federal laws no longer apply, when until a year ago it was generally understood that agencies like DEA had guardrails even when trying to apprehend people on felony charges?
If this stands, there is no logically consistent rationale for DEA not being able to perform warrantless wiretaps of all communications, etc.
The crime starts when the border is crossed, it doesn't end once you are illegally in the country and travelling domestically.
We do not give other law enforcement similar deference, even though it might help them in some fraction of cases. For example: SEC could prosecute more insider trading if it was able to wiretap all domestic communications.
Air travel in the United States is mamanged by Federal law, not state. This is solidly in the Federal law enforcement wheelhouse. Anything that crosses state boundries is ALSO under Federal law.