This achievement is for completing the tenth mission of the game and can be obtained on any difficulty.
Here's my playthrough of Mission 10 - Transfer Orders on normal.
Aircraft used: F-15E
Special weapon: 6AAM (6 air to air missiles)
Score required: None (Normal)
Time limit: None (Normal)
I would recommend heading out in front of the transport aircraft, which takes a slightly winding route towards the middle of the map. You'll see the line of allies if you zoom all the way out - that's where the plane is going.
While ranging out ahead, quickly eliminate the SAM sites as you see them. The sites won't show on the map until you're close but you can locate them visually by following the vapour trails heading up from the surface.
When enemy planes appear on the map, head over and eliminate them ASAP - they're far more dangerous than the SAM sites. I failed a few times before I realised that while the SAM's do some damage, the transport planes counter measures will deal with most of their missiles. The Enemy fighters however, will take down the transport quickly and with little difficulty.
After the enemy drone shows up it's simply a dog fight - if you have any special air-to-air missiles left, now would be the time to use them.Tip: I played through a couple of hours of multiplayer, gaining enough MRP (in game currency) to purchase the F-15E which made this a lot easier and more fun than the starting F-16C. Around Mission 12, I had enough to purchase the F-22A which is the most capable aircraft I've found so far. The currency, planes and most part upgrade unlocks work across multiplayer / singleplayer but some upgrades are exclusive to multiplayer. You can also go into 'Free Mission' to replay for some extra cash.