I didn’t get to all of these last week, did I? I just had a lot of other stuff on my mind, and I’ve found it’s easier to write about what’s going on then to try to fit to a specific schedule. That doesn’t mean I forgot you guys! I’ll be playing catch up this week.
JB: (1) I redeemed Avios points for Air Berlin award tickets between Miami and Germany in economy class. Is there any way to upgrade these flights using points or cash? (2) I am renting a car in Berlin to drive toward Berchtesgaden over a few days. Do you recommend renting with a company in the U.S. or Germany, and can you recommend one?
You could always change the award and rebook it into a higher cabin class using more points. This depends on award availability. Upgrades for cash are not likely, but I do not have direct experience with Air Berlin. Some carriers do offer them. They are usually something like a buy-up offer to first class immediately after booking an economy class award while the reservations window is still open. However, an airline will almost always be more accommodating to its paid customers. If someone is going to get a buy-up offer, the person who paid for his or her seat will have higher priority over an award traveler.
For example, British Airways says their Avios points can be used to upgrade flights, but only revenue flights and only those booked for travel on American Airlines, British Airways, or Iberia:
You can use Avios to upgrade to the next cabin when you make a cash booking with British Airways, Iberia or American Airlines, although the next cabin varies by airline and route.
Let’s get on to the second question about renting a car in Germany.
I have heard good things about Sixt, but I have not rented a car before outside the U.S. I’m not sure I can provide a useful recommendation in this case, but do make sure you check whether any liability coverage provided by your credit card company extends to rentals in Germany. Ireland and Italy are common examples of countries excluded from most policies.
You should be more concerned with something like the difference between a stick shift and an automatic. I have no idea how to drive anything but an automatic transmission. Many cars in Europe have a manual transmission. If you need a particular type, make sure to request one when making the reservation. Also check if you will need an international driving permit, which is basically a passport-like card that offers a translation of your current driver license (which you still need to carry with you).
Renting a car from a company with U.S. offices, like Hertz, National, or Avis, will make it easier to negotiate with the firm if anything should happen to your car during your time in Europe. However, Sixt has a large presence in Germany and is expanding to the U.S., so you should consider them, as well.