Since the original post asked: "how do the magazines get to the airlines," I have some answers...

Basically, these niche magazines authorize their distributor to unload "extra" titles through the airlines. The magazines use this distribution in an effort to boost their circulation numbers, which are the primary driver of page rates and thus revenue. Non-paid circulation (e.g. magazines sent to the airlines) is heavily discounted by advertisers, but publishers use the channel to boost their overall circulation number, or to prop up circulation that is falling. Media buyers all know the ruse, but it's an old publishing trick to meet your "guaranteed audience" target.

As for titles like "Technology Review," I imagine that MIT has a hard time moving it on the newsstand. There is certainly a prestige issue at work, and I can only imagine that the school believes there is a benefit of having a wider audience.

And HBR is a mystery to me, since it's not a consumer title and more of a trade publication that isn't shilling for advertising.

You're less likely to see major mainstream titles (Time, People) that have newsstand traction. Getting a magazine for free through the airlines is a pretty good sign that there is a problem on the business side for a publisher.

(www.accessabc.com or www.magazine.org for more information)