Uho: no, commercial airline schedules are printed am and pm.
Before the internet, the grandaddy of all airline schedules was the monthly edition of the OAG (world edition, North American edition, etc.) and flight departures and arrivals were, and I presume still are, printed thus: 700a 330p for a 7:00 am departure and a 3:30 pm arrival. I tried the OAG site now to see if their website is the same as the book, but they require (free) registration which I didn't feel like bothering with. Nevertheless, popular air travel sites like Orbitz, Expedia, and Travelocity all use the am/pm convention. (And, by the way, they all use mm/dd/yy[yy] format as well.) I'm pretty sure all American airlines (United, Northwest, Delta, American, Continental, USAir, Southwest, JetBlue and dozens of others) also use am/pm as well, though I admit I haven't checked them to verify this.
Wolfson: I believe you, but where is it located, and in what context is it using this style? On the top of their letterhead, when sending a typed letter to another business? I would be surprised if they were located in the U.S. and using that style for business correspondence, though not at all surprised if it were used for computer generated reports, internal project planning and anything requiring computer sorting for which it is the obvious best choice.
Finally, in the US, unless there's something to be gained from it (like with a commonly agreed computer interface such as TCP/IP, for example) people and businesses tend to ignore standards dropped from on high. The fact that some book or government agency would come out and say "you should write dates this way" would be universally ignored. Just like we ignored the 1970s era recommendation that the whole country should switch to the metric system. There are still a few road signs printed in kilometers, and they're but a curiosity now.