To answer your question, a good priest once told our group that he was allowed to say two Masses daily, and three on Sunday. This priest is in the Archdiocese of Washington, D.C. The pastor at my current parish (I live in a different diocese) also re-iterated this one Sunday from the pulpit, saying that a priest could only say two Masses on weekdays (I think a third can be said if the Mass is a funeral) and three Masses on Sunday.
I think our pastor brought this issue out in the open since some parishioners apparently complained about Mass Times, and the availability of priests. I recall when he was on vacation (and the parochial vicar was on vacation) one summer that for two months there was only one daily Mass at 5:30 p.m. Our pastor was able to put directions and Mass times to neighboring parishes (i.e. all within a 15 minute drive) when there daily Masses were being said in the mornings. By the way, this worked out well, and since only one priest was at the parish for two months (the pastor and the parochial vicar took turns taking vacation), the one priest was able to be available for appointments, sick calls, funerals, unexpected circumstances, etc., even though there was only one daily Mass at 5:30 p.m.
Today, our parish now has three priests, and there are three daily Masses on Mondays, Tuesdays, and Thursdays, and two on Wednesdays and Fridays. The 8:00 a.m. Friday Mass is also the weekly school Mass. The most well attended daily Mass is the one at 5:30 p.m., because people stop off on their way home from work (many businesses are located in close proximity) to attend Mass (it also is a good excuse to wait for the rush hour traffic to cease).
As far as the military, I don’t know. That would be up to Archbishop Timothy Broglio, who is IMHO a good bishop. I do know that sometimes a priest is not able to make it to remote places on Sundays. I know a Navy Chaplain who served in Iraq, and there was one base he could only get to on Wednesdays.
