IF you could get the door open far enough at cruise speed to actually exit the aircraft.
I've got about 150 hours in the 150/152 and a similar amount in the 172 and it'd be tough to hold the door open at cruise speed while you wiggle out. The doors on these aircraft hinge forward into the airstream. You'd have to hold the door forward, wide enough for you to fall out, into a 100 mph wind, while you exit the aircraft backward, all without calling attention to your movement? Tight isn't the word for a 152 cockpit. The instructor would have been alerted immediately to the roaring, loud enough to make you think the plane was coming apart. The noise would commence as soon as the door started to open, causing a slight, but noticiable pressure change in addition to the noise. Something isn't quite right with this story.
I don't know what to make of this, no conspiricy theory, it's just strange.
There's a LOT that's not right with this story. You began with the noise of opening the right door on the 150. Let's continue with the fact that the open door's disruption of the air flow will not only cause the loud roar BUT also dramatically change the flight characteristics of the aircraft. The open door would immediately create a low-pressure area, which would quickly un-coordinate any turn the pilot had initiated. In other words, the open door would IMMEDIATELY command the PIC's attention. For him to report that he glanced over and saw the right-seater's FEET leaving the plane is almost comical.
My guess is that the guy was never on the plane to begin with. That small field would be ideal for someone to take off with a "purported passenger" who really wasn't - because there would likely be no witnesses either way. So the pilot is in on the "rearrangement" of Filler's life - and the location of Mr. Filler is probably far far out of the country at the moment.
If you want to get out of the US with no one noticing, there are plenty of ways to do it. You can walk right over the border into Mexico, and once there, you can open a bank account with a new identity, and you can also travel to just about anywhere with a Mexican departure - and no one is any the wiser. There are plenty of places that you can do the same thing in entering Canada unnoticed. You can also exit the US at any number of seaports quite easily. If you have documents that look auth, you can escape US detection quite easily once you're out of the country.
Michael
I understand the 152 uses the Lycoming instead of the old workhorse Continental and claims to squeeze a few more knots out . . . but never having flown one I can't say.
As I said, my flight instructor used to routinely open the door in flight and hang his leg out. He'd brace his foot on the strut. The slipstream did tend to hold the door closed, but not in any overpowering way. My dad used to open the window on his 1967 210 Centurion in flight - noisy, but it didn't rip the window off the airplane or anything. I think there are "dead zones" of air along the sides of the fuselage, particularly given the bulky engine cowling right ahead of the door.
All that said, this whole episode has my antennae gently vibrating. It seems very odd that the instructor-pilot didn't immediately radio the tower that his passenger had left the aircraft and give at least general bearings and landmarks. I flew with a flying club out of a small field near Atlanta, and we all had a very good relationship with the ATC guys. I would have been on the horn as quick as I could grab the mike. Hooks Field has a tower: David Wayne Hooks Memorial Airport Perhaps since they were at 9,000 feet they had climbed well away from the field (takes a long, long time to get a 150 up that high), but in that case I would have called Houston approach or SOMEBODY.