Built-in defensive system on the Party Planner, guarding against ground-based anti-air fire.
Listing the Party Planner's defenses for Florin, Louis named his own Protect Aircraft shield plus an Anti-Flak Shield that came with the aircraft, and an upgradeable stealth mode. The ship's system description confirms only "rudimentary shields" alongside forward and aft anti-air guns, which is why the Casket in the Sky class is joked to require a pilot with gonads the size of bowling balls to enter fortified airspace. Side protection is absent — Florin flagged the flanks as vulnerable and was told door guns are an upgrade.
Stock protection against anti-aircraft fire, insufficient on its own for contested airspace.