The Shrike is a flying vehicle. With default configuration, left-click fires the Shrike's primary cannon, which has a four-round magazine. Right-click uses the afterburner, which provides a speed boost in-flight. In contrast to previous Tribes games (Tribes 2, specifically), the Shrike cannot fly right or left, but the afterburner still doubles as a vertical jet. By pointing directly upwards and then turning (gimble locking), the turn speed of a shrike is greatly increased. It is safe to accidently knock into friendly shrikes as you will take no damage although the physics of the two vehicles colliding will make for an odd break away. Shrikes cannot be purchased by heavy classes.
Shrikes are most often used to chase the enemy flag carrier as it's generally very easy to catch up with a Pathfinder. Hitting a light or non-shielded medium class midair will instantly kill them, and take off a large portion of a heavy's health. Another common use is to destroy Beowulf tanks that are in a particularly difficult place to reach by other means.
While there is only a single real anti-vehicle weapon in the game, the Saber Launcher, you can't rely on Doombringers to deal with shrikes by themselves. Shrikes take damage from all explosive weapons, and attacking them whenever possible is highly encouraged. You can often bait the pilot to ram you mid-air; while you may get run over and killed you'll be in the perfect position to land a very hard hitting projectile on the shrike before your demise.
Explosive weapons such as the Soldier's Spinfusor or Technician's Thumper may be hard to land on a fast moving flying vehicle, but Assault Rifle and SMG projectiles can rip them to bits too and much quicker than most people think. By keeping the pilot under constant pressure from rapid-fire projectile weapons you also minimize the effectiveness of approaches the shrike can make. A shrike can also easily go down if the pilot is killed, resulting in a one shot kill on the vehicle. Using the disk strategy requires that you aim where the pilot will be, rather than where he is. However if the pilot is flying straight at you in an attempt to ram you then a single Devastator Spinfusor disc will destroy the shrike unless it is at full health since it does over 3000 damage.
It is possible for a Sentinel to use his rifle to snipe the pilot out of his shrike. This is incredibly difficult to do, but it can be the only way to take out shrike pilots who are adept at dodging explosives.