I don't get it. Why would CBP and ICE need to buy this from a data broker? The TSA is right there scanning everyone's boarding pass as part of going through security.
It is not even certain that the data actually comes from the TSA. It could come from airlines, payment companies, etc.
There is no guarantee of quality when purchasing data from a broker.
They're spending public money, so the cost doesn't matter to them either. With this administration they can get unlimited funding.
But you're proposing something even more outlandish, asking another agency for data. The politics of this are mind bending. If one one agency give their data to another and that agency is successful using it it will make the giving agency look bad which is unacceptable. It was wild how many times another, supposedly friendly agency, would not share data. In fact, I was cautioned not to even bring up the idea in shared meetings because it would create unnecessary friction.
If you buy it from a 3rd party government contractor, none of this has to happen.
It's kinda like how the police need warrants to request cellphone data, but cellphone companies could sell realtime data to third parties who in turn sold it to the police.
Flight purchases would be critical and distinct information for law enforcement.