Advanced Config

The second choice of the "configuration" menu.

12 parameter categories are configurable

Campaign Preferences

Flight

Mission AI

From 0 to 4: allows you to set the level of the AI.

Mission ground Objects

Fighter Mission types

Bomber Mission types

Recon Mission types

Transport Mission types

Target Types

Aircraft Numbers

Mission Limits

Management of escorts.

Escorts will always be limited due to game performance issues. If you want to be sure you have an escort:
Configuration -> Advanced Config -> Mission Limits -> Max virtual escorts
Configuration -> Advanced Config -> Mission Limits -> Odds (%) <flight type> mission is escorted: from 0 to 100 (100 → always escorted)

If you want more hunters besides escorts:
Configuration -> Advanced Config -> Mission Limits -> Max fighter flight of each camp.
Increasing the maximum number of flights will not increase the number of escorts.