Apparently Al once said "if you can't explain what you are doing in plain English, you're probably doing something wrong", which I guess means the general theory of relativity is pure bullcrap.
Bob riffs off this to "If you can’t describe what your model says in plain English without provoking derisive laughter, it probably doesn’t say anything of value”, and says Macroeconomists should take heed.
I must say though, that I've never thought it was hard to say what DSGE models were saying in plain English without getting laughs. I did find it so hard to say what textbook Keynesian models were doing with a straight face that I had to quit teaching intermediate macro.
Bob then returns to his main theme, an appreciation of all things Kahn:
"Many disgruntled air travelers remember him unfavorably as the chief architect of commercial airline industry deregulation. But as he was quick to remind critics, planes now fly with many fewer empty seats than they used to, resulting in much lower average fares, after adjusting for the sharp increases in operating costs that have occurred in the interim."
Um, I'm pretty sure there was a lot more to airline deregulation than decreasing the number of empty seats on flights. There was entry, there were new routes, there was the opening of air travel to the middle class. In short the industry was transformed in a way that massively benefitted consumers.
I'm not sure why Bob is so conflicted that here in his homage to Al, he feels the need to take shots at Al's crowning achievement.
Bob then ends with a heartwarming story about how kind and beloved Al was:
"A story circulating at the time described an English professor’s complaint to him about the high salaries of economics professors. “Perhaps you should consider starting an English consulting firm,” he is said to have responded."
If I didn't know better, I'd think Bob didn't actually like Al very much.