Goat Simulator – How to Kill a Goat

There are

• Angel Goat - Gives a halo and increases jump skills.
• Devil Goat - Gives devil powers as an R toggle ability.
• Ripped Goat - Increases attack strength.
• Tall Goat - Is tall
• Feathered Goat - Moves faster
• Giant Goat - Is giant
• Robot Goat - Is a robot
• Space Goat - Spaceeeee. (Also a pain to try and play as.)

In addition to these, there are mutators that, while they may change only a little visual appearance of your goat, they give you additional R power. These include:

• Pitcher Goat - R ability to 'throw' balls.
• Jetpack Goat - R toggle ability to fly!
• Blue Streak - Can charge up spin attacks like sonic.
• Yoshi Goat - Can lick objects, then press r to turn them into bombs.
• Goat Queen - R ability to summon peasants.
• Goatborn - R ability to fus-ro-dah!

As far as I know, only Angel Goat, Devil Goat, Ripped Goat, Pitcher Goat, and Jetpack Goat can be used in a non-custom game. The others can be used in custom games.

Unlocking Goats:

Goats that are unlocked through collecting a certain number of goat trophies:

• Tall Goat
• Feathered Goat
• Giant Goat
• Space Goat - Collect all trophies.

Goats that are unlocked by touching certain objects in game.

• Jetpack Goat - At construction site, on 2nd highest level.
• Pitcher Goat - At batting cage next to spawn.
• Goat Queen - Throne in palace reached by climbing goat tower at spawn and going in top door.

Goats that are unlocked by completing certain objectives in game.

• Angel Goat - No rag dolling pedestrians for a certain time.
• Devil Goat - Bring 5 sacrifices to the Goatacle.
• Ripped Goat - Defeat all goats in the goat fighting ring.

There may be more, so if others are found, feel free to edit this answer and add them to the list.

Update: 1.1 Added the following new goats

Uncle Goat:

• Unlock by walking into the room in the building next to the skate park. There will be a large alien-ish container that has it.

Classy Goat:

• Get 5 golden goat trophies.

Shopping Goat:

• Get 20 golden goat trophies.

Builder Goat:

• Find one of the 3 minecraft blocks.
• There is a cobblestone block at the graveyard, past the wind turbines.
• There is a dirt block up the hill next to the skate park, near some trees, to the right of the 3 boulders of death.
• There is a wooden block by the thickest tree closest to the shore, across the water from the theme park.

DeadGoa7:

• Go near/lick DeadMau5. He will be at the top of the skyscraper. You can get there through the lift inside, at the bottom.

Repulsive Goat:

• Enter the sewer. It is at water level, next to the bridge.

Tornado Goat:

• Get the tornado sculpture on top of the middle wind turbine, and bring it to the wind altar, located between the skate park and the dam.

Double Jump:

• Unlocked by default

Rocket Skate Goat:

• Get 30 golden goat trophies.

Hitchhiker Goat:

• Bring a towel with the number 42 on it to the crashed UFO near the dam. You can get the towel next to the pool, at the second highest roof party of the skyscraper.

Here are video guides for every achievement in Goat Simulator. On the bottom of the page, you can find the "Mile High Club — Lick the Hanging Glider" achievement, which I think is the one you are looking for.

Same as you tried: you must climb up the big crane and then jump on the glider when it's close enough to lick it. It's the last video. Watch at 0:30 to see how to perform the jump to reach the glider.