For something baked to be Mezonos it must fulfill one of the following requirements:
- The dough is so liquidy one cannot roll it in one's hands and one fries it in a pan.
- The dough is so liquidy one cannot roll it in one's hands and one fries it in a hole in an oven (so it gathers in one spot and becomes thick there).
Pas Habaah Bekisnin - There are three opinions as to what this refers to:
- Normal bread that was kneaded with a majority of fruit juice.
- Some say that the above mentioned "PAs Habbah Bekisnin" is normal bread. This opinion says that "Pas Habbah Bekisnin" is bread that we filled with a sweet filling before baking (so the filling is the ikkar and the bread is the tafel).
The Halacha is that one could rely on the first opinion, but a Baal nefesh should be stringent and wash on normal bread before eating.
Mezonos bread served on an airplane is "Pas Habbah Bekisnin" of the first variety. It is made from water and apple juice, so technically, it is a mezonos. As "flat bread" isn't on this list, it is Hamotzi.
This list is for Ashkenazim only. The Beis Yosef does add "flat crackers" to the list of "Pas Habbah Bekisnin" and therefore, SEfardim don't wash on Matzo year round.