The Lucid's roofline is about 4" lower than the EQS. However, Zak Edson, Lucid's head of Retail Operations, actually is 6'6" tall, and he didn't have any problem with headroom when he sat in the backseat at the Miami studio to demonstrate the leg room. That is because the rear seat cushion in the Air is low, which causes the knees-up sitting position).
When I sat in both the front and back seats of the Air, I did notice the thickness of the roof rails. However, with the glass canopy the car didn't feel too claustrophobic. But then, again, I, too, am only 5'7" and the car was inside a showroom. No matter how you parse it, the Air does have a high belt line -- not as extreme as the old Audi TT, but hardly the expansive side picture windows of a Land Rover.
On another note, I've been going back and forth with the author of "The Driver Download" video channel. He said the Air will not have an air suspension. I found a Lucid job posting for a "Senior Engineer - Air Suspension" and September 2020 articles by both "Motor Trend" and "Car & Driver" that said the car does have an air suspension. However, the author said that in a recent visit to a Design Studio he was told the car would NOT have an air suspension. He contacted a Lucid media representative who confirmed this. He asked for more details about the suspension and is waiting to hear back.
It seems that somewhere along the line Lucid has abandoned an air suspension. More and more features of this car seem to be dropping by the wayside.