Konvoy operations for Orks follow ancient rules and long experience. Light armor on most Ork aircraft and some aliens, and on the rear of almost all aircraft guide the reasons for these operational rules. Other threats like koptas, jetbikes, and similar craft are handled in similar ways.
Ork trukks fulfill many roles in Ork armies, with only roughly a quarter being used for personnel transport. Usually half of an Ork trukk fleet are used to ferry supplies, with the rest used for specialized tasks mostly related to mekboys and kommandos, like technical support, wreckas, electronic warfare, information warfare, and other oddboy tasks.
Even specialized versions of Ork trukks are armed. Almost any mix between big shootas, rokkits, and any other weapons provide adequate defense to konvoys, when attentive air watch is maintained. Passengers with big shoota, rokkits, and other capable weapons like kustom mega blasters and such add an unknown element to attacking aircraft.
Konvoys consist of six or more vehicles. Groups of one of two vehicles have inadequate capability to defend against air threats, but still can take risks to complete small missions. Small groups of 3-5 trukks have inadequate defense to reliably resist predations of single aircraft. Six or more trukks or vehicles make for adequate konvoys against singular aircraft threasts.
Trukk-only convoys of only six trukks are inadequate to defend against the predations of two aircraft, but represent enough counter-threat to limit attacks by other than the most skilled aircraft pilots. Konvoys of twelve or more mostly trukks should be accompanied by Flakka trukks, or other capable anti-air such as lootas or or tracta guns en portee (guntrukks.)
Inbound aircraft warnings need to be immediately shared with other konvoy members. Countering air threats should be the highest priority for small independent konvoys. All vehicles should immediately deploy to aggressively engage enemy aircraft from advantageous vectors utilizing the great speed of Ork trukks. Counter air fire should focus on and deploy toward eliminating one aircraft at a time. While deploying to counter the air threat, konvoy members must not disperse so much to get scattered.
While trukk-mounted and other capable weapons are the primary anti-aircraft weapons for konvoys, all personal small arms should also be directed at light armor facings to improve overall probability of target destruction.
If attacked by aircraft skwadrons with more aircraft than one per six vehicles, the flee air alarm should be sounded and all konvoy members should scatter and conduct air defense as best they can. The possible escape of some vehicles represents a better outcome than the destruction of all.
This guidance for spans unknown millennia and serves Orks well. Natural Ork aggression combines well with this guidance for results that serve well.