The RCMP lists air soft under air guns in the air gun fact sheet:
http://www.rcmp-grc.gc.ca/cfp-pcaf/fs-fd/air_gun-arme_air-eng.htm
Note that air guns wouldn't require a PAL even if they exceed 500 fps if they don't meet the energy threshold (5.7 Joules/4.2 foot-pounds) - steel BB guns wouldn't exceed the energy threshold until close to 600 fps if firing 5.4gr BBs, while airsoft guns firing 0.2 gram (3.1 gr) pellets wouldn't exceed 5.7J until 780+ fps
I did a little more research into this as it seemed contrary to what I remember and according to the government website:
http://laws.justice.gc.ca/eng/acts/C-46/page-18.html
Certain weapons deemed not to be firearms
(3) For the purposes of sections 91 to 95, 99 to 101, 103 to 107 and 117.03 of this Act and the provisions of the Firearms Act, the following weapons are deemed not to be firearms:
(a) any antique firearm;
(b) any device that is
(i) designed exclusively for signalling, for notifying of distress, for firing blank cartridges or for firing stud cartridges, explosive-driven rivets or other industrial projectiles, and
(ii) intended by the person in possession of it to be used exclusively for the purpose for which it is designed;
(c) any shooting device that is
(i) designed exclusively for the slaughtering of domestic animals, the tranquillizing of animals or the discharging of projectiles with lines attached to them, and
(ii) intended by the person in possession of it to be used exclusively for the purpose for which it is designed; and
(d)
any other barrelled weapon, where it is proved that the weapon is not designed or adapted to discharge
(i) a shot, bullet or other projectile at a muzzle velocity exceeding 152.4 m per second or at a muzzle energy exceeding 5.7 Joules, or
(ii) a shot, bullet or other projectile that is designed or adapted to attain a velocity exceeding 152.4 m per second or an energy exceeding 5.7 Joules.
So according to this (the government of canada's own criminal code website), it does not need to meet both the velocity and the energy to be considered a firearm. I think the rcmp website might still be worded incorrectly...