My manager told me that I have to work 5 hours a day not to be docked the hours I have asked off for. I work various hours per week. Attend night meetings and trips that include long flight hours, meeting hours, entertaining hours, etc.

All based on company policy.
Normally your salary is based on a set number of working hours, although this should also include so method to calculate paid leave.

I trust that you keep a detailed daily calendar. Exact hours for everything!
If you are not an indispensable employee, and they balk at vacation requests, then it's time to get policy made clear.
If they don't have clear policy, then invent one for them.
What's a plane trip worth, and a night meeting, and a weekend meeting?
Assign each type a multiplier of an hour in house during a normal work week.

If they don't like it, start looking for another job. If they don't let you go.
Negotiations take guts.