Okay, I am not usually one to complain but everyone has his or her limits. Please be patient with me as I am sure you all have been through this countless times before but I need clarification on a few points as working as a civilian is new to me.

I work in the telecommunications industry in a supervisory capacity, which as far as I can tell makes me an exempt employee because I also earn mire than the minimum annual salary. I routinely work 16 to 18 hour days not counting commuting time (In a company vehicle carrying necessary tools for the completion of assigned work). So I guess my first question starts here; Is there any maximum number of hours a person can work in a day when driving is an integral part of the job and takes up about 50% of the work day?

Now my next questions deal with compensation for hours worked. Three weeks ago I had to take time off for a family issue (no I do not yet qualify for FMLA) and only worked one day of the week in question, a typical 18-hour shift. When I received my paycheck it was lower than I expected, go figure right. Upon closer examination I saw that I was being compensated 13 hours for PTO and 8 hours for the day I worked that week. Now I realize that my employer equates a day with 8 hours because when I get a pay stub for a week in which I was present all week it states 40 hours times what ever my hourly rate is if one were to take my annual salary and divide it into 52 forty-hour weeks. So my question here is should I be compensated for 21 hours as I was or am I being shorted 10 hours? I think we all realize what the honorable thing to do is but how many of work for truly honorable companies?

Finally while I was gone I became Ill and was advised by my physician to remain at home for three days the following week. (This was a really bad month all around.) Now on one of these days I had to go see a different doctor at the mandate of my manager the appointment was made and paid for by my company. I am not being paid for this day or the other two that I was out. The only reason I have questions about this is that there are no provisions in the company handbook outlining any type of sick leave plan. Would this absence of a "bona fide" sick leave plan prohibit my employer from docking my pay for sick days?

If, in fact, you meet the criteria for exempt status, and let's assume you do, you are not entitled to any additional compensation, time off, or anything else over and above your weekly salary. And no, there is no limit to the hours the employee can expect you to work. That would be true for nonexempt employees in Maryland as well.

As an exempt employee, the weekly rate breaks down to a daily rate, depending on the number of days you are scheduled for in a week (it can be 5 or 6). If you take four days off of a 5-day workweek, then your salary can be docked 4/5. The hours/hourly rate is merely a requirement of most systems. Besides, FMLA is unpaid leave. It appears the employer has paid you correctly by paying you for one day (8 hours) plus the remaining PTO you had in your bank.

Regarding the sick pay issue, yes, a PTO plan normally includes all reasons, including illness. If the PTO plan provides for at least 5 days of time off, and you had used it all up, your salary could be legally docked for full day absences due to illness.
http://www.dol.gov/dol/allcfr/ESA/Title_29/Part_541/29CFR541.602.htm

I understand that the FLSA deems it acceptable for an employee to work 168 hours a week what I was wondering is if there is any other laws state or federal that cover employees that are expected to drive a vehicle for the majority of their shift like truck drivers

There's only a maximum # of hrs. for interstate truck drivers.