"on schedule," "behind schedule," and "ahead (of) the schedule"
"I am sorry Mr. president, we are running behind ___ schedule."
"The airplane has to take off now, we are already running behind ___ schedule."
What should go in there, if anything. Dose it depend on the situation?
I guess my question is about the usage of "the" with respect to the phrases
"on schedule," "behind schedule," and "ahead (of) the schedule."
Would you shed some light on this for me please?