It took same work, but I've engineered a fool-proof method for infiltrating the Ice Base. Iceberg was built for this sole purpose. It's a transforming vehicle that can switch back and forth between off-road mountain climber and poweful jet with a single touch of the landing gear button.

As a ground vehicle, Iceberg's wings help aid its suspension by producing minimal lift, making short hops less likely to damage the vehicle, and give a tiny bit of air control. The jet engines can also be throttled up slightly to boost speed and help climb very steep slopes. Pressing AG7 allows you to rotate the turret using VTOL and Trim. AG1, and AG2 fire Infernos in clusters of eight, crucial for bypassing the ice base's laser defenses. The vehicle is operated on the ground like a typical car using pitch and roll.

In the air, Iceberg handles like a typical airplane. But you must resist the urge to retract the landing gear, as doing this transforms the plane in ground-mode, making the plane uncontrollable in the air.

And now for the mission:
Start at Avalance Airport, and transform into car mode, and switch to Air-to-Ground targeting. Drive along the same path you take during the Snow Crawl race. Slow down once you get to the final hill that puts in targeting range of the missile launchers. Activate the turret movement with AG7 for fine-tuning your targeting. Slowly climb the hill (use the minimal jet thrust for help climbing), and peek over the hill to lock onto one of the missile launchers. Once locked, press AG1 to launch a volley of 8 missiles, then reverse to hide behind the hill to avoid any incoming missiles. Once you notice one of the missile launchers was destroyed, repeat the process and press AG2 to launch the second volley. Of course, remember to hide again to avoid any more missiles. Once both missile launchers are destroyed, aim for the hill to your left. Transform into plane mode, then throttle up and use the hill as a lauch ramp. Once in the air, you are free to attempt a landing in the ice base. Use 5% throttle for your final approach. If you come in too hot, switch to ground mode to utilize the more powerful brakes on those wheels.

Also armed with 2 machineguns.