Not that it has absolutely anything to do with that "Aeromail" cover, but as an aside, you can identify that in New York City on November 7, 1929, the Museum of Modern Art first opened to the public. Based on this Wiki quote it was further noted that it was exactly nine days after the Wall Street Crash.
An interesting piece of postal history that you can identify with that postmark.
Quote:
The idea for The Museum of Modern Art was developed in 1929 primarily by Abby Aldrich Rockefeller (wife of John D. Rockefeller Jr.) and two of her friends, Lillie P. Bliss and Mary Quinn Sullivan. They became known variously as "the Ladies", "the daring ladies" and "the adamantine ladies". They rented modest quarters for the new museum in the Heckscher Building at 730 Fifth Avenue (corner of Fifth Avenue and 57th Street) in Manhattan, and it opened to the public on November 7, 1929, nine days after the Wall Street Crash. Abby had invited A. Conger Goodyear, the former president of the board of trustees of the Albright Art Gallery in Buffalo, New York, to become president of the new museum. Abby became treasurer. At the time, it was America's premier museum devoted exclusively to modern art, and the first of its kind in Manhattan to exhibit European modernism.