Est. time allowance after arriving FRA

It usually takes between 30-45 min. to emerge into the main part of the airport from the luggage pick-up. From this point, you will go upstairs by escalator to the rest of the airport with all the check-in desks and find the escalator that will take you to the Monorail that whisks you to Terminal 2. This walk may take around 10 min.+ / - a few min. Depends on how crowded the airport is. The monorail takes about 1 or 2 min. then you would just go downstairs to the rental car place. I would guess anywhere about an hour if you find your way ok.

Check in of course takes longer. Always allow 3 hours for flights back to the states. I can imagine that yes, you will need to check those hiking poles. Having never rented a car in my life, I can't help you with the time frame needed to pick-up or return a car. I am sure that others will help you with this.

I do know the airport pretty well though.

The only time I rented a car in Frankfort took quite a while due to a language barrier. We waited in line about an hour. Departing will, as Jo points out, take much longer. You'll need to be there 3 hours before departure not including turning in the car. The rental attendant did a very thorough search of the car for security reasons. This added about another 30 minutes and we were first in line. The attendant, who looked like a terrorist, went over the car with a fine tooth comb glaring at us the entire time. Of course he didn't find anything but gave us this "I'll catch you next time" look as he signed off on the car. It wouldn't have been funny except I was there with two aunts and an uncle and at 51 was the baby of the group. They ranged from 60 to 71 and were about the least suspicious group you can imagine. So if you look at all suspicious, allow even more time!

On a recent trip to Germany, we also landed @ FRA in the early morning - about 6 30 am. Maybe due to the early hour, or maybe we just got very lucky - but there was hardly anyone waiting in line @ any rental desk. We signed our paperwork, and were in the garage picking up our car in just a few minutes. I wouldn't COUNT on not having any lines when you pick up your car, but maybe you will get lucky as well. From walking through the terminal, to customs, to luggage retrieval and car rental, we were out of the airport and on the road within 1 hour of arrival.

Car return was also quick and no more complicated than here in the USA. Everything was well marked, and there were attendants available to check us in. No big deal. Just remember to top off the gas tank in advance if that is part of your rental agreement ... there is a Shell station right outside the airport, if i remember correctly, but not too many others that are easily accessible.

If you're bringing hiking poles, I'm assuming that those will need to go into oversize baggage. There's a separate check-in area for that. When we were there last summer checking my son's car seat, there was only one agent working the oversize baggage check-in. We already had a tag on it (we checked in at the train station), but there was a family in front of us with a lot of sports equipment and a dog. We were waiting there for about half an hour. With that in mind, you might want to get to the airport 4 hours ahead of time. Worst case scenario, you get a lot of time to shop and spend any euros you have left over.