Mexican Airmail Commemorative Cover Query

There is an awful lot happening with this cover. It has three Labels applied to the envelope; the Arrow, the airplane, and the 1930 PAA Mexicana all tied with the winged hand stamp.

Can anyone supply a history for this? What is being commemorated or inaugurated or .... ?

Can't supply a history, but it's a great looking piece.

Nice cover, a lot happening there.

The 2 postage stamps appear to be SG479(1929) 20c, and SG494(1930) 1c on 2c.
The sticker at the bottom of the envelope is for the inauguration of the airport.
"The [Mexico City International] airport first opened as Balbuena Military Airport with five runways. The first landing was on November 5, 1928 and regular service started a year later, but was officially inaugurated on May 15, 1931. Its first international route was to Los Angeles International Airport operated by Mexicana." Wikipedia
The purple cachet at the top is explained here:
May 1931
Roberto Fierro, como encargado de la Aeronáutica Civil mexicana, organiza la "Decena Aérea" y la "Exposición de Aeronáutica, Comercio e Industria", con motivo de la inauguración del Puerto Central Aéreo y el Edificio Terminal de la Cd. de México. Se carece de mas datos.
Roberto Fierro, as head of the Mexican Civil Aviation, organizes the "Ten Air" and "Aviation Exhibition, Trade and Industry" on the occasion of the inauguration of the Port Central Air Terminal Building and Mexico City. More data are lacking.

Thank you! That is a great deal more than I knew before. It's too bad that the postmark itself is so indistinct. Central across the bottom and Aero on the upper right but that's about all. The date is also indistinct - I have it as 19 May 31 7 PM - but the supposed "9" could be a "5" if that configuration of addons was only used the one day.