What is TX DPS Air 1 and Air 2?
Air 2 is a fixed wing plane with a lot of surveillance equipment, including a camera system that can downlink video to units on the ground, like a mobile command post. Air 2, N243TX, was used extensively hear in the Dallas area when the initial protests got out of hand, with some participants looting or simply trying to destroy other's proper. Texas has two of these planes, initially acquired to enhance border security.
More about the Air 2 craft can be hound here:
Texas Department of Public Safety officials say the high-dollar aircraft with...
www.expressnews.com
N90TX is usually DPS 101 based at Mesquite Airport east of Dallas. However they move them around a little, I would suspect it is done when one is down for maintenance.
I've noticed the same thing, seeing several other tail numbers on Flightradar24 that are identified as copters owned by DPS, while at the same time hearing the helicopter talking to one or more agencies on the ground, during a search or chase, using the radio call 'DPS 101'.