Here is the history..
With the recent popularity of Mexican food and wraps in general, flour tortillas are now a very popular subject. With a little practice you will discover they are much easier to prepare than corn tortillas and that it is just as easy to make great ones as ordinary ones!
Anxious to be able to prepare their staple breads, Spaniards brought wheat seeds with them to Mexico. Unfortunately, wheat did not do well in the humidity and heat of southern Mexico. It was not until years later when Spanish settlers arrived in northern Mexico that they found the dry cold winters required for the crop to flourish. Ironically, by that time, the Spaniards were accustomed to Indian foods and quickly adapted wheat to the preparation of a new type of tortilla.
Being close to northern Mexico, flour tortillas are very popular in the United States, where they are widely available in supermarkets. Another reason why flour tortillas are so popular is that really good corn tortillas are almost impossible to find in the United States, and difficult to prepare, while top quality flour tortillas are relatively easy to make.
All flour tortillas are similar in ingredients and preparation but not in size. They vary from about 4 inches to about 18 inches in diameter, and in thickness from paper-thin to over 1/8 inch thick. Generally, the largest, thinnest tortillas are found in the Mexican state of Sonora, where burritos are thought to have been invented. There, it was discovered that dried meat wrapped in very large flour tortillas could be carried in saddlebags and, if necessary, eaten with one hand while riding a horse. This style of flour tortilla is also popular in Baja California, Arizona, California, and New Mexico. One exception is Tex-Mex cooking where thick, puffy flour tortillas are used in place of bread, and to wrap fajitas and other fillings.
The most common flour tortilla size is what I call the all-purpose flour tortilla, and has a diameter of about 6 1/2 to 7 ½ inches, and is less than 1/8 inch thick.