As to the fleet, they are all the same aircraft, every single one of them was once at ExpressJet, and was shifted by UA to C5 or Trans States. Really. So while the 25 still operating at EV (ExpressJet) are many of them the slightly older, 145LRs not 145XRs, they are not dead. (And let's just put the new to airliners myth that any aircraft at or near 20 years old needs to be parked immediately to rest! The 145 is built like the Emb-120 was - it's a tank. Properly cared for, she's good for plenty more years. I don't love them, and I don't love saying that, but it is true. Just like the 30 year old 767, make the inside look new, give them new paint, and nobody cares how old they actually are.) At the moment, only ExpressJet has been capable of doing the heavy checks, so UA had them do so, then hand freshly checked XRs to C5.
And yes, myth number two, even the pilots inside ExpressJet don't seem to realize that they are indeed only flying 20-25 aircraft, not 90. They are the smaller of the two entities right now. In September UA has them down to 20 planes. They are being wound down. Still, that same EV pilot group is promising not to take any concessions and to die on their swords. Hoorah, gentlemen... way to kill your airline! The flight attendants have been told by the head of their union, the redoubtable IAM, one Sara Gonzales that she will accept any concessions on their behalf to keep the airline alive. (Fun fact, Sara Gonzales is also the person who represents the flight attendants at Commutair!)
Finally, UAL sent either four or five additional VPs to ExpressJet with very generous salaries in the last year and a half, which oddly did not result in the departure of any existing VPs. This is par for the course at ExpressJet, very few people have ever left the HQ, in fact, the legacy ExpressJet HQ in Houston is also fully staffed with duplicate functions now dragging on the payroll. Not a single person has taken a paycut, VP or otherwise and no one has been reduced in force since the departure of the ASA 200s, the 900s, or the 700s that flew as Delta Connection, or American Eagle, excepting the large number of furloughed Flight Attendants. Which means there are now something on the order of 30-40 people in HQ per aircraft. Those are not people who make $9/hr. They are also long time folk whose salaries have gone up year after year regardless of actual performance for 20+ years.
Which is why when ExpressJet sent WARN notices everyone in the company got one. (And timed so that the 60 days will end on ... Sept. 11!)
You might note that there hasn't been so much as a peep about even a single WARN notice at Commutair.
And the EV maintenance base that did those heavy checks on the E145LR and E145XR fleet - CLE, has been told that they are definitely closing. (I think it's a safe bet that C5 will have a hiring event for mechanics in CLE real soon, and likely open an MX base there, in a hangar rented by UA perhaps?)
I don't see any conclusion possible except one: dead airline flying it's last.
ExpressJet is reportedly behind on its bills, (with the exception of payroll).
I see SkyWest 200s in UAX paint arriving in Houston suddenly this September.
And no, no merger. ExpressJet's pilot group has been part of killing ExpressJet multiple times, nobody in their right mind wants that group as anything other than zero seniority new hires firmly told to be quiet.
Former ExpressJet headquarters employee here. A few responses to your points:
1) E145 commonality: This may have changed, but C5 is not certified to fly the non-XR 145s. Cannot remember the specific reason, but this is why C5 only took XRs. At one point, I heard this difference came as a surprise oops moment to UA when the C5 program was starting up.
2) EV Fleet size: You're right - the fleet was shrinking and shrinking. I think we had around 20 spares on a 110 aircraft fleet at one point. Even with the "massive growth" charade from new ownership, we couldn't staff those and the new 175s. UA was not happy paying for parked planes.
3) Headquarters Staffing: ExpressJet was and still is thin on VPs. The VPs of Flight Ops, Maintenance, HR and Finance, as well as the Tech leader, left within the first year of the sale. New ownership brought in 1:1 replacements (Tech was upgraded to VP). There were a couple new SVPs brought in to fulfill duties SkyWest previously handled. For the most part, there were not duplicate functions in Atlanta and Houston. I agree that headquarters headcount was still high in some areas, given the smaller size of the company, but we most definitely laid off people following the Delta and American terminations. We were also supposed to be in growth mode after the sale, which explains some of the headquarters staffing. About the pay - no one at ExpressJet headquarters is making what they should be for the amount of work required, even VPs. The pay is embarrassingly low.