FIFA 11

Certain players in FIFA 11 has traits/ specialties attached. These include "playmaker", "crosser", "aerial threat", "distance shooter" and "poacher". If you perform certain tasks with a player with these abilities, you'll get an achievement.

To get the "Aerial Threat" achievement, play as Manchester United and stick Nemanja Vidic (he's a defender) upfront as a striker. Keep crossing the ball and if he heads one in, you'll unlock this achievement.

You can do so on any difficulty level. I won this achievement on Amatuer.

PS: Since Ryan Giggs (crosser) and Dimitar Berbatov (poacher) are in the same Manchester United team, you could do all three achievements in one game.

All of the other sulotions are good but they all tell you to do it in kick off or career mode but that is slow and boring.

To get this significantly quicker go the options and then Arena Options then choose Chelsea as your team as they have Drogba who has the aerial threat speciality then go to the main menu and press "B" or "back" this should take you to the arena now press "back" again and select a practice piece now keep on taking corners and hitting it to Drogba until he heads it in.

Look for a player with the Aerial Threat, Drogba(Chelsea) is one of them. Keep crossing the ball to him and you will have it in no time. Remember to play on amateur.

Further to the excellent solution written above by HollowxIchigo15..

I would just like to add, it may be worth doing what I did and playing a 'crosser' on each wing, as well as 2 Strikers both with the 'aerial threat' ability to speed up proceedings.

So just to emphasize:

Kick-Off > Exhibition Match
Team: Rest of World > Classic XI
Opponent: Any 1-3* team just to make things that bit easier, or even randomise the selection if you're not fussed!

It may be worth putting on 20 minutes half lengths so that you don't stress over time remaining in the shorter matches.

I changed the formation to 4-4-2 and played;
Zico (right footed crosser) in the 'RM' position,
Hugo Sanchez (left footed crosser) in the 'LM' position
Alan Shearer and Rudi Voller in the RS and LS positions who both have the 'aerial threat' special ability.

It's makes it a whole lot easier with this team crammed full of mid-high 80 and low 90-ranked players,

For an average FIFA player such as myself I managed to get a cross from Zico headed into the back of the net by Alan Shearer on the '8 minute' mark of a match against West Bromwich Albion.
Netting me 20G for 'Crosser' and 'Aerial Threat'.

They easiest way to obtain this achievement is to play on amateur and select the classic XI as your team and play against a low class team(like Stockport).

Then put two aerial threat players in front and one crosser. Keep crossing the ball in with the crosser and you will probably get it within one match.

My winning combination was:

Aerial Threat: Eric Cantona & Rudi Voller
Crosser: Hugo Sanchez

This is by far i know the easiest way to get this chievo