I just stumbled upon a short 'note' paper (Macia et al. 2004) in the Journal of Molluscan Studies, entirely by accident, that describes numerous observations of flying squid. Not just gliding squid (which I never thought of before), but actual, powered, controlled flight in squids. There is some speculation in the paper that this ability may be generally absent from individuals larger than about 30 cm in length, but just because nobody has seen larger squid flying, doesn't mean they don't do it (and snatch and devour any person who witnesses such an event). They report one observation of a 120 cm long individual of the species Dosidicus gigas, seen jetting water while airborne (i.e. powered flight) in 1964 off the coast of Chile. Some individuals of other species are reported to hold their tentacles in particular aerodynamic positions, and flap their tentacles or fins, while airborne.
I'll let their chilling concluding paragraph speak for itself:
While there is some question as to the exact nature of airborne jet propulsion in squids, we believe use of the term ‘flight’ is not wholly inappropriate. Morphological traits such as broad fins and arm membranes, as well as airborne behaviours including jetting and changes in arm posture suggest that flight has evolved in squid, most likely as an anti-predator behaviour. Such traits also suggest that flight represents a more active and intentional escape behaviour than simply gliding after an incidental exit from the water during escape jetting. Whether considered flight or gliding, however, this behaviour appears to be more widespread than previously thought.
AAAAH! I am scared!
Macia S, Robinson MP, Craze P, Dalton R, Thomas JD. 2004. New observations on airborne jet propusion (flight) in squid, with a review of previous reports. J Moll Stud 70: 297-299.