Before you ever go to the vehicle pad, you may want to go to settings and un-invert your vehicle controls. I'm not sure why inverted is default, it seems like everyone always flies their first shrike straight into the ground as a result, then never wants to buy one again. You can also turn up the sensitivity of the vehicle controls, although this may make it harder for you to aim accurately, just adjust it to whatever number feels right to you.
Technician is the most common choice for a shrike pilot class as you can get out of the shrike and repair, however this takes you out of the battle for quite a long time, so it's often easier to just buy another shrike if the generator is up. For that reason I usually use pathfinder as my pilot class, so I can be more effective at shrike capping (discussed later), and be able to return to base and buy another shrike quickly if I get shot down.
Pilot and Wheel Deal are the two obvious choices.
Getting the final pilot perk is a must, as it allows you to eject whenever the shrike is destroyed. Often when facing another shrike, they will end up ramming you, destroying both vehicles. With Pilot fully upgraded, you get the kill, a nice bonus for taking down their shrike, and you can keep your killing spree going. It can also quite useful if you hit the ground when trying to roadkill the flag carrier as it will propel you out and you can continue the chase.
Wheel Deal will allow you to get a shrike much earlier in the game, reducing the price of a shrike to 3150 when fully upgraded, which is very helpful because it allows you to get a shrike earlier, and once you get used to flying them, it's quite easy to rack up another 3150 credits before you have to buy another, so you can stay in the air for the majority of the game.
Start a training match and buy a shrike.
To start, just get some altitude and fly around until you get the hang of the controls. Once you get used to them, fly lower, and try to fly through obstacles. If you are playing on Katabatic or Sunstar, flying through the open parts of the towers is great practice. Try to fly as fast and low to the ground as you can without crashing as this will prepare you for roadkilling opponents. Once you feel comfortable enough, head to one of the free shrike servers and get ready for combat.
Shrikes have two weapons, the plasma bolts (fired with M1), and the shrike itself, which tends to be a far more useful weapon once you get the hang of roadkills.
As a shrike pilot, your main duty is to defend the area around the base, and chasing flag carriers. When patrolling for enemies it's best to fly fairly low around the base in a path that takes you right next to the flag stand (though it's a good idea to fly just to the side rather than directly over it, so you don't get hit by mortars or strikes intended to clear the stand). Watch the enemy pathfinders and try to find their flag routes. If you know what route they are going to take every time, it makes it very easy to swoop down and hit them midair. If possible, it's best to do this by hitting them from the side, or back as it reduces the chances of them being able to shoot you before you get the kill. If following closely behind a flag carrier who is trying to take you down, it's best to not follow directly behind them, but fly in a zig zag pattern, swooping in for roadkill attempts then getting away before they can take a shot.
The main use for the shrike's guns is finishing off ground units and combating enemy vehicles/defenses (Things you don't want to run in to). It's very very difficult to hit a player in midair, so if you're chasing the flag carrier, wait for him to land. The projectiles travel fairly slowly, so you may have to fire just before they land to get the kill. In addition these have some knockback, so you can use them to toss enemies into the air, then get them with a roadkill. The projectiles do travel long distances though, so on very small maps like Crossfire, you can take aim at the enemy flag stand from your base when you're defending.
Besides the threat of being shot while attempting a roadkill as previously mentioned, there are two main threats to the shrike: Doombringers and other Shrikes.
The easiest way to deal with them is avoidance. These guys usually just hang around their own base defending, so they don't become a problem unless the map is tiny, or you have to chase a carrier to their side of the map. If one gets frustrated enough to walk all the way across the map to fight you you know you're doing something right.
If they are on the other side of the map, it's probably best to leave them alone. If you do get the kill, they'll be back in 5 seconds to fight you again. However, they can become a problem if they get to your side. While missiles can easily be dodged by hiding behind a hill, this forces you to stop watching the base for a few precious seconds to hide from their sabers. If you find yourself being targeted by missiles, try to determine where the missiles are being launched from, and look for the doombringer. When you see him press alt to alert your teammates of his presence. Usually they will be on top of a hill to get missile lock on you, so fly at the hill, shooting at him. Try to force him up in the air and go for a roadkill, although realize that it may take more than one hit to kill a doombringer and be prepared to make another pass. If he is about to get missile lock, use your boost to fly over his head as fast as possible and he will usually lose lock. If at any point during your fight, the flag is grabbed you should probably break off and chase the flag carrier instead, as even if he does get missile lock, you can outrun the saber for long enough to run down the carrier in most cases.
This depends a lot on the other shrike pilot, some will attempt to win by shooting you down, others will just ram into you killing you both. If you have the credits for another shrike, and the pilot perk, the generator is up, and you're near the vehicle stand, running in to them isn't a bad idea as it lets you get back to protecting the base quickly. If you don't, and the other pilot is attempting to dogfight you rather than just ram into you, try to get behind them. Shrikes turn slowly enough that it's easy to stay behind and shoot them down. Do not try to stop and hover while shooting at them, as this leaves you vulnerable to attacks from ground units. You can also take advantage of gimbal lock to make tight turns in dogfights. By flying straight up and then rolling, you can make a much tighter turn than if you just moved the mouse sideways while flying level to the ground.
Any class can stand on it, making it great for ferrying heavies to the very top of the tower on Sunstar, or bringing sentinels to the cliffs on Temple Ruins. Watch out while you're picking up teammates though as it leaves you vulnerable to attack until you can get in the air again.
You reach very high speeds when ejecting from a shrike, so you can use this to get 300+ Sanic grabs on most maps quite easily. just fly towards the enemy flag stand and press g. This should obviously be done from back to front for best results. (It's also a great way to get the e-grab if you've chased the enemy carrier back to their base but haven't been able to kill them)