When parking a manual transmission vehicle near an aircraft, which gear should it be placed in?

When parking a manual transmission vehicle near an aircraft, placing the vehicle in reverse is the most appropriate choice. Parking in reverse engages the reverse gear, which helps prevent the vehicle from rolling away due to gravity. This is particularly crucial in an airfield environment where safety is paramount and even a slight movement of the vehicle could pose a risk to the aircraft or personnel. Additionally, parking in reverse ensures that the vehicle is firmly secured on an incline, as the vehicle's weight is better distributed in a way that resists rolling.

While other options like placing the vehicle in neutral or first gear might seem viable, they do not provide the same level of security against unintended movement. "Neutral" does not engage any gear, meaning the vehicle can easily roll. "First" gear can provide some resistance on a flat surface; however, it is not as effective as reverse for stabilizing the vehicle when parked near aircraft. The "Park" option is specific to automatic transmissions, which are not relevant in this context since the question pertains to a manual transmission vehicle. Therefore, selecting reverse is the most effective and safest choice for securing a manual vehicle in such an environment.