I find some of the missions in military bases quite hard. Apart from getting a Rebel Drop, is there any other way to call the Rebels for help?
While liberating a base big enough, Annika might tell you that she is sending in rebel support. She will tell you to do a task, like hack all the SAMs for air support. You cannot call in rebels, but she will usually offer this support for big bases once you destroy about 1 to 2/4ths of a base. The rebels won't destroy chaos objects, but they will attack any form of militia, giving you cover.