Slightly ahead of schedule, part three (runs and screens) will be up in a few weeks. I may write a post about the use of formations, the next offensive scheme as off now will be flexbone, then potentially the run n shoot or oregon spread.
The Airraid would not be as deadly as it is without it's quick passing game. Having the ability to get five to ten yards a throw consistently and quickly allows these teams to move the ball at will when they are playing well, and teams use a variety of concepts to move the ball if defenses line up wrong. These plays are all relatively low cost in terms of practice time, but if perfected can put defense in a bind very quickly.
We will start with an Airraid staple, all hitches. Hitches starts off, and is read by the quarterback, much as four verticals does. The slot receivers take their routes inside and settle in the zones about 8-10 yards off of the line of scrimmage. The outside receivers try to release straight and settle 8-10 yards off of the line off scrimmage. The quarterback's job is too find the receiver farthest away from a defender, take a step back, and throw it to said receiver. This running back checks to see if anyone is blitzing, if not he will check release to the flat, however he rarely gets the ball on this play.
Another favorite, especially out of trips, is the stick concept. The flanker to the trips side runs a fade route, the quarterback will occasionally throw this on rhythm but it is mostly to occupy deep defenders. The next receiver will run an out route, allowing the quarterback to throw underneath the flat defender if he is running with the fade. The furthest inside receiver will run a quick hitch, settling inside the outside linebacker/safety that is playing the flat. The quarterback hits the inside receiver, who is in essence going wherever the guy covering the out isn't, as his third option. On the backside the flanker will often run a route signalled in, typically either a slant, fade, out, or hitch (the route doesn't matter so long as the backside defenders must be aware of him). The backside flanker is often the stud (see Ok. St.'s use of Blackmon) and will be thrown to if he is in a one on one situation. The back will check release to the flat on the backside, allowing the quarterback an outlet if he can't throw to any of the receivers. The quarterback will take a step back and read from the flanker to flanker, going horizontally, with the last read being the runningback.
This is the smash route, and it occupies a strange space between quick passing and dropback. Some teams run it as a full dropback route, some teams run it as a quick play (with shallower routes), still others run it as both. Regardless of the depth that it is run at the goal of the play is still the same. One receiver will run a post route, attempting to wind up underneath the deep safety. Another receiver will run upfield, then backtrack to a point 2-3 yards off of the line of scrimmage. The quarterback is reading the flat defender, in essence if he covers the post throw to the flats, and vice versa. This play is a staple versus cover 2 teams. The quarterback will take his quick/dropback steps and read the flat defender, often with another route combo tagged to the backside of the formation in case the defense is in man coverage. The runningback will often run the route he uses on four verticals, although he will occasionally check release to the flats depending on the backside route.
The next quick passing play in the arsenal of an Airraid team is Y corner/Z spot/Snag. This is another trips concept (although with this and stick you can always use a back as the flat route and run another concept backside) designed to stress zone defenses, as well as providing some natural run routes versus a man defense. Despite what the good people at EA would tell you the quarterback's first read is the post route (LB), although much like stick the goal is to occupy the deep defenders. The next read is the receiver running a snag route (B), his job is to run a slant and sit the second that he is open, this route will often turn into a slant versus man. Finally the quarterback will look at the receiver in the flat (A) in case the flat defender over pursued the snag by the flanker. The backside receiver and running back are used the exact same way in this play as they are in stick. The quarterback will take a one step drop and read post-snag-flat-flanker backside-running back.
A final quick passing play is the slant concept with slots running flat routes (although these often are bubble routes). This is a route combination designed to have the two receivers cross, thus picking each others defenders. The outside receiver will run a slant, breaking on his third step and looking for the ball. The receiver heading towards the flats will get to roughly where the flanker started out, and then look for the ball. The quarterback is taking a quick step back and firing to the flanker if he's open, or resetting and reading the flat. Often teams will run another concept backside, with the quarterback reading pre snap to see which concept he wants to throw. The back will check release, alternately on his four verts get open route, or to the flats as a final safety valve.
These plays all offer certain solutions to issues that a defense can cause, it is up to the offense to either call or audible into the right play. This is what makes pre-snap reads from quarterbacks (and post snap by the coaches) so important. These plays can be stopped, however most of the time a team is giving something up to stop them, and it is up to the offense to find and exploit it.