That whole policy seems a bit out of line. In the past, I've been able to make a deal with my employer when they would not pay for extra legroom seats. I expensed the cost of the ticket they would cover and paid the extra out of pocket and bought the ticket myself. I didn't like paying even a part of work travel but at 6-4 it was pretty much necessary. I made that pitch and they bought it. And since I was buying the ticket, I got the miles.

I don't know if your employer will be that flexible but it might be worth a discussion.

As for travel on my own time, I have always gotten either OT or compensatory time, no question.