My girlfriend and I are landing in Tempelhof Airport before noon and leave Tegel Airport a little after 5pm the same day. With the layover time, we were thinking of going on either a city tour bus, the 100/200 bus route, or possibly splurging on a private sightseeing car tour.

Does anyone have experience with this or any other suggestions? We would hate to go wait at the airport for hours when we could be out in the city exploring. However, with luggage, the hassle of connections and expense is it worth it? Any advice would help.

How much luggage will you have? When do you have to be at Tegel to take your flight (1, 2, 3 hours beforehand)?

It'll take at least 1/2 an hour to get out of Tempelhof and make your way to the S-Bahn. You might have time for lunch somewhere in town, but if you have big suitcases, they would probably be a hindrance.

You'd have to figure out how much time you'd have roughly before knowing whether you can get out in the city.

Good points. We will have 1 large piece of luggage and 2 smaller carry on items. I figure we have 3 hours max. between baggage claim, check-in, and transportation.

You can see a bit of Berlin in 3 hours, but your luggage remains the problem given that you're only "passing through".

In that case, look into whether it's possible to store your luggage somewhere, like Tempelhof or the main train station, but subtract the time to go back and get it from your estimated amount of free time. Then decide whether it's worth it to do some sightseeing.

Could be an option to take northbound subway line 6 (look for the signs with an "U" for Underground) from Tempelhof AP to Friedrichstrasse station (also a train station). Leave luggage there in lockers.

Walk to Unter der Linden avenue, upscale shopping in Friedrichstrasse, Brandenburg Gate, new US Embassy, Reichstag building (all in 10-15 min walking distance). You can see all of the above in 60-90 min even if you rather stroll than walk fast.

Go back to Friedrichstrasse station. Take again subway line 6, again northbound, to Kurt-Schuhmacher-Platz, change there to airport bus 128 destination "Tegel Airport".