The water vapor was very cool, too bad I had a crummy lens on.
Edit: See Contrail Creation #2 on Wikipedia for a discussion of this effect: "The wings of an airplane cause a drop in air pressure in the vicinity of the wing (this is partly what allows a plane to fly). This drop in air pressure brings with it a drop in temperature, which can cause water to condense out of the air and form a contrail but only at higher altitudes. At lower altitudes, this phenomenon is also known as Ectoplasm. Ectoplasm is more commonly seen during high energy manouvers like those of a fighter jet, or on jet liners during takeoff and landing, at areas of very low pressure, including over the wings, and often around turbo-fan intakes on takeoff."