There have been a number of different versions of the American flag throughout its history. The 13 stripes on the American flag represent the original 13 colonies; so, the number of stripes remains unchanged. However, the number of stars on an American Flag represent the current number of states; so the number of stars on the flag depend on when the flag was made.

The 13 stripes on the American flag alternate between red and white and they represent the 13 original colonies:
The American flag is displayed for a number of purposes.
There are specific guidelines for flag display known officially as the Flag Code which include:
There are also requirements for displaying the American flag. When placed vertically, the stars should be displayed at the top left hand corner. Those wanting to display the flag have the option of using a regular flag or those decorated with gold fringe.
There are a number of ways to fly the American flag. In general, the American flag should always be flown above all other flags, such as a state of commercial flag.
There are certain occasions when the flag should be flown at half staff. This is usually determined by the President of the United States on a national level and by the governor on a state level. The flag is usually flown half staff after the death of a public official such as:
The flag is also flown half staff for certain holidays which are commemorative of those that fought in wars. The half staff flying of the American flag only occurs permanently at the governmental national cemeteries.
In all, the flag has been changed 26 times since its inception. There was a time in 1795 when the stripes were changed from 13 to 15 to represent the entry of Kentucky and Vermont as states. Later in 1818, Congress passed a plan that would officially reduce the stripes to 13 to represent the original 13 colonies while adding a new star each time a state was admitted.
Many people have presented designs for future flags in case Puerto Rico or the District of Columbia is accepted as a state. These designs will feature a change in the number of stars, but never the stripes on the flag.
The new flag design would go into effect the first 4th of July after the acceptance of the new state.
Regardless of the design chosen, the number of stripes on the American flag will remain at thirteen stripes to represent the original thirteen colonies.