"Yup. That helicopter works alright. But you killed the pilot. Course, there was another fella, can't remember his name." — Waldo Zimmer, certified aeroplane mechanic
Speak to Waldo Zimmer, the mechanic at Drassen Airport (B13) to get information on the missing helicopter pilot, hints to his whereabouts, and to activate the quest. A small amount of leadership is needed to get Waldo to open up.
The pilot will be located in one of the random swamp sectors northeast of Drassen. Explore the area, and a message will appear (Your squad has noticed someone in Sector xx: Swamp.) when you cross over the sector the pilot is hiding in.
Drop into tactical view, and you'll see a house nestled amongst the water and foliage. The pilot, named Skyrider, is inside, and a friendly demeanor and will get him talking to you, as long as the speaking merc's leadership is not cripplingly low.
There are 4 possible locations where Skyrider can be found. This is generated at random every game. After accepting the quest from Waldo, you can talk to random civilians in C13 and eventually one of them will say something about a swamphouse in a particular location. This give you an easier time to find Skyrider. If the civilian said South West, then it will be in D12, South East means E14, directly East means in C16, and North East means B15.
Once he's talking, he'll express interest in making a business deal with you if you can escort him safely to the airport in Drassen. Take him directly back and lead him over to his chopper to complete the quest.
Access to swift transportation via airspace over Arulco, for a cost.