Those are almost certainly general depictions of (then) existing aircraft, made a bit sleeker out of artist whimsy…Even Bono’s saucer HLLV likely had more thought put to it—even if it was just a notional design to show the advantage of ROOST having a simple rocket shape.
To an artist of the era…a rocket that becomes a dot on ascent and a plane that does likewise…it’s all the same.
That one requires so much more energy than the other isn’t obvious to a layman.
When that artwork was made, it seemed that there was no limit….going from biplanes to the XB-70 in that art…people thought that such radical advances were here to stay—if not accelerate.
Today’s corporate art is more likely to just show images of young mothers…single parents…in some kind of an outfit or uniform.