There's a guard post near the starting area and it's defended by two guards. It's best to avoid this area, because it's heavily defended.
You must return to the parking lot after killing the mission target.
Areas where you can climb the fence in order to reach the next part of the military airfield.
You can use the coins to convince the airport security guard to change his position. This will allow you to attack him and to gain a new disguise. A soviet soldier can also show up here - you can subdue him as well so that you'll be able to get another disguise. Hide both bodies in a large crate.
Alternatively you can use the radio from the guard post to distract nearby enemies.
It's guarded by the airport security and you can head there if you're using the soviet soldier disguise.
Other entrances to the building
Make sure that you're using the airport security or the soviet soldier disguise.
There are a lot of soldiers near the northern entrance (the one to the hangar) and they can recognize Agent 47 if he's wearing the same clothes - avoid them or use the airport security disguise.
You can sabotage the generator which is providing power to the nearby floodlights. One of the soviet soldiers will show up here to inspect the problem - you can subdue him and obtain a new disguise.
Climbing this gutter will allow you to reach the western rooms on level 1 (the KBG officer's quarters is among them).
Climbing this gutter will allow you to reach the eastern rooms on level 1 (the radio room will be among them). You can also use the gutter to get to the roof (level 2).
You can use the rat poison (green 2 on the map) on the bottle. This will allow you to poison one of the mechanics working on this jet. You can then follow the guard and get his disguise or make it easier for yourself to eliminate Knight using the jet's ejection mechanism (red 1 on the map).
A single mechanic can be found here. You can easily subdue him and collect a new disguise.
You can begin your exploration of the building here if you've used the eastern gutter (blue 8 on the map).
There are two of these objects here (more of them are in other parts of the building). A wrench is needed to sabotage the ejection mechanism of the jet located in the hangar (red 1 on the map).
Emetic rat poison
You can use the poison on the vodka botle (as a part of the assassination of Jasper Knight - red 3 on the map) or on a bottle found in the hangar (blue 9 on the map). The second method will allow you to poison one of the mechanics working on the jet.
It's in a locker room with two of the airport security guards.
Note for KGB High Command
Reading this note will allow you to find out about the possibility of killing Jasper Knight in the radio room (red 7 on the map).
You must sabotage the jet's ejection mechanism and since you can't be discovered it's recommended to poison one of the mechanis (blue 9 on the map). Wear a mechanic's disguise, go to level 1 and talk to Jasper Knight. Return with him to the jest and find the safety procedures ont the crates. You must initiate the training prodecure so that Knight will die when the ejection malfunctions.
You can carry the bottle to the KGB officer's quarters (red 3 on the map) and apply some poison there.
KGB officer's quarters
You can poison Jasper Knight here. You must place a vodka bottle from level 0 (red 2 on the map) on the desk, apply the poison (green 2 on the map) and also tamper with the chess game. Jasper will then drink vodka with the KGB officer and go to the toilet (red 4 on the map) where you can silently kill him.
Jasper Knight will show up here after you'll poison him in the KGB officer's quarters (red 3 on the map). You can drown him in the toilet bowl.
You can go with the slides to the projector located on level 1 (red 6 on the map).
You must insert projector slides found on level 0 (red 5 on the map) and wait for Jasper Knight to take interest in the projector. Sabotage a nearby fuse box. Knight will try to repair the projector and he will be electrocuted.
You must subdue in the KGB officer somewhere where it's quiet and take his disguise. You can then talk to Jasper Knight, go with him to the radio room and quietly kill him when he's standing next to the radio. Hide his body afterwards, but watch out for a guard patrolling a nearby balcony.