Is it necessary to have a passport number in order to buy an air ticket from
Berlin to Ulaanbatur via Moscow?  My son will be taking a trip with a friend
from Berlin.  His friend says he will buy the tickets but needs the
passport number.  My son's passport has expired and he won't be able
to renew it until
after this college semester in June.  His trip begins August 20, 2005.

Greetings!
I have good news for you a passport number is not required at the time
of booking.  Most sites which offer overseas booking list a passport
number as an optional field when filling out a reservation but none
require it.

I verified this in two ways.  First I attempted to book the trip you
described using a couple of the major online booking sites, most
notably Expedia.  I was able to get up to the payment section (the
last part of the reservation process) without having to enter a
passport number.  The only thing that stopped me from booking tickets
was the fact that I didn't want to enter my credit card number (I
don't really plan on going to Mongolia in the near future).

To be doubly sure I called up the international reservations
department for a number of international carriers (British Airways,
Delta Airline and Lufutunsa) and asked them if they required a
passport number when booking.  They all said no and didn't know of any
countries or reasons why it would be mandatory.

Finally, I called two local travel agents that I found in the phone
book and asked them and they said no as well.

Your son should be fine to book tickets now and renew his passport over the summer.

If you have any questions or need something cleared up please request
a clarification before rating my answer and I will be happy to help.

Best,
djbaker-ga

Excellent. Thorough and quick.

Hi,

I actually had the same problem for my friend who's traveling for the
summer & I found a site where the passport issue didn't come up. I was
able to book the ticket and hae to worry about the passport. I
actually gave them a call also just make sure everything was fine, he
was very helpful, I think sam was his name. The site is
www.mi-travel.com. If you are going to call ask for sam, he helped me
out.

Good Luck!