While in some continuities the Quinjet comes in pairs (Or as a Decpticon in a certain awesome crossover), it seems we are only getting one in this film. While the original Quinjet was made by Wakandians, it is more likely this iteration will be designed by Tony Stark or S.H.I.E.L.D.. The primary use is to get Avengers around who can't fly while the ones capable of flight flank it. You get some really classic comic imagery out of this.
We see interior shots with many different settings such as a conference style room, a laboratory, and of course and armory. It is pretty much a flying fortress of awesome operated by S.H.I.E.L.D.. Speaking of S.H.I.E.L.D. ...
Pretty much the only cast member, aside from Stellan Skarsgard, not shown in the teaser, to much dismay. Maria Hill is essentially Nick Fury's right hand woman. If Nicky needs something done, she can execute it. She will be played by Cobie Smolders from How I Met Your Mother, and it will be nice to see what she can do as an actress outside of her role as Robin.
Arguably one of the most popular 'comic events' in recent memory (The only one I think in the past 10 years that eclipsed it was Flashpoint, but I don't think the event of Flashpoint was as exciting as the complete universe shift/reworking that resulted in the 'New 52'). The event centers around the separation of Superheroes because of a bill being passed through congress to regulate metahumans. This splits the entire Marvel universe into two distinct groups: Pro-Registration and Anti-Registration. Pro-Reg is led by Iron Man and Anti-Reg is led by Captain America. And the two beat the crap out of each other constantly. The playful banter in the trailer is a long way off from Iron Man decking Captain America in the face, but it is a starting point.
Everyone got a few cool shots. Thor calling his hammer, Steve Rogers mounting his shield to his back, Iron Man flying through New York. Everyone except for the Hulk. The Hulk gets a shaky cam style rage moment where we see his face transform from Banner to Hulk. While it is the very definition of a tease, I really was looking for a bit more out of Ruffalo, after all he is the only one that didn't star in a film before hand and I was looking to see at least a small inkling of what he would be bringing to the character.
The music choice of Nine Inch Nails was a stunning and inspired idea, and I commend who ever at Marvel Studios or Paramount or where ever decided on it. Really sets the tone of everyone having to come together and work as a team. All said, I cannot wait for May 2012!