What do these countries have in common?

Question

The following alphabetical list contains independent countries with a certain common property. (The list is complete to the best of my knowledge).

Australia, ???, Chile, Costa Rica, Cuba, ???, ???, Iceland, Laos, Liberia, Luxembourg, Nepal, Netherlands, ???, ???, ???, Panama, Russia, ???, Slovakia, ???, Thailand, ???, ???

Which countries have been replaced by questionmarks?

Answer 1

The answer is:

All of these countries have red, white, and blue flags.

Here's the list of question marks (in order):

Cambodia, Czech Republic, France, New Zealand, North Korea, Norway, Samoa, Taiwan, United Kingdom, United States

Here's what I think your source was:

http://en.wikipedia.org/wiki/List_of_flags_by_color_combination#Blue.2C_red_and_white, and in this case it seems like Costa Rica may not count.