Question(s) about orientation flights

[jalentour]

Why do so many bees orient at the same time?
How long do they orient?  I watched them until they spiral out of sight. 
Other than getting their bearings, are there other purposes to the orientation flight?
Do they only have one large group orientation flight?

[AR Beekeeper]

Honey bees make their first flight when they are about 6 days after emerging.  It is a flight to take their first dump and their first chance to orient on their home.  There are hundreds of bees emerging every day, so the flights can be made up of hundreds that emerged on the same day, and their sisters that came before them, but had a need to fly also.

They fly as long as it is necessary to get the job done.  The young bees will make later flights of longer duration, they will cover more area with each flight.  At about 14 to 21 days they are mature enough for long flights and will start to forage as they are required.