"What do the colors of the flag mean?"
According to custom and tradition, white signifies purity and innocence, red, hardiness and valor and blue signifies vigilance, perseverance and justice.
"Is it correct to say that certain stars in the blue field represent certain states?"
There is no legal or other authority for saying that certain stars represent certain states in the blue field of the United States flag. Still, it is logical to conclude the first star in the upper left corner represents the first state admitted into the Union and that the last star represents the last state admitted. Reading from left to right then, and top to bottom would represent the various states in order of their admission into the Union.
"Is it permissible to display another flag or pennant above the flag of the United States?"
The flag of the United States always flies above other flags, with one exception. During church services conducted by naval chaplains at sea, the church pennant may be flown above the U.S. flag during services for personnel of the Navy.
"Is the Government required to fly the flag every day?"
Yes, the flag must be displayed daily on or near the main administration building of every public institution, in or near every polling place on election days and in or near every schoolhouse when school is in session.
"What is the significance of displaying the flag at half-staff?"
This gesture is a sign to indicate the nation or state mourns the death of an individual. Normally only the President makes the decision to fly the flag at half-staff, but this decision may also be granted by governors and mayors.
"What size flag is appropriate to be displayed from a flagpole?"
Tradition - and good taste - says the length of the flag should be approximately one-fourth the height of the flagpole.