In the conflicts of present day and the near future, having close air support for your ground troops is vital. Aircraft can provide a high vantage point to the battlefield and get fields of fire that no ground troop would be able to manage. Then there's the maneuverability factor. In Team Yankee, your British troops can be supported by a set of Harrier Close Air Support fighters.
The Harrier is armed with a 30mm Aden 5-chamber revolver cannon and BL-755 anti-tank cluster bombs. It's ideal for breaking up enemy tank formations and harassing enemy troop movements. Being able to take off and land vertically means they can be kept hidden away in unconventional locations close to the front, helping protect them from enemy air strikes during rearming and refueling.