"The flag is customarily flown all year-round at most public buildings, and it is not unusual to find private houses flying full-size flags.
Some private use is year-round, but becomes widespread on civic holidays like Memorial Day, Veterans Day, Presidents' Day, Flag Day, and on Independence Day.
On Memorial Day it is common to place small flags by war memorials and next to the graves of U.S. war veterans. Also on Memorial Day it is common to fly the flag at half staff, until noon, in remembrance of those who lost their lives fighting in U.S. wars."source: Wikipedia
"The flag has been displayed on every US spacecraft designed for manned flight, including Mercury, Gemini, Apollo Command/Service Module, Apollo Lunar Module, and the Space Shuttle. The flag also appeared on the S-IC first stage of the Saturn V launch vehicle used for Apollo. But since Mercury, Gemini and Apollo were launched and landed vertically and were not capable of horizontal atmospheric flight like an airplane, the "streaming" convention was not followed and these flags were oriented with the stripes running horizontally, perpendicular to the direction of flight."
source: Wikipedia
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