Hot-air balloon flight normally take place at the beginning or end of the day. Passengers may find themselves at the launch site before the sun rises above the horizon or in last final hour of daylight. The explanation for this is simple physics. the lift generated by hot air rising is proportional to the temperature difference between the hot air in the envelope and the cooler surrounding air. The nylon fabric of a typical envelope can withstand a maximum internal air temperature of about 120C, so a lower ambient temperature allows a larger temperature difference and greater lift. Consequently, it is easier to obtain the lift required for a flight before the sun warms the air.
A balloon is prepared for inflation and flight by a ground crew. The first step is to lay the envelope, or canopy, out on the ground with the basket and burners attached. This process offers good photographic opportunities in its own right, but do not get in the way of the ground crew as they check that none of the lines are entangled and that the vents in the canopy are closed. Powerful fans are then set up to blast air in to the envelope and begin the inflation process. Once the envelope contains sufficient air, the propane burners are used, in short blasts, to insert more and more hot air. This process also offers good photographic opportunities. Members of the ground crew may enter the envelope as the inflation process proceeds to check that everything is in order, but do not follow or walk on the fabric unless invited to do so. In appropriate shoes may damage the fabric of the canopy and it is very dangerous to remain inside the inflating balloon for too long. If the envelope takes off with someone inside the unfortunate person will be lifted in to the air and then dropped to the ground.
Balloon envelopes are of huge capacity and easily disturbed by the slightest breeze. When partially inflated they are particularly unstable, so keep well away and follow the instructions of the experienced ground crew.
Hot-air balloon baskets are generally as the name suggests - giant whicker baskets made much like traditional shopping baskets. They are normally about four to five feet in depth and equipped with a strong floor, a leather-covered rim and a number of internal handles for passengers to grasp during landing. Passengers must climb over the rim of the basket to get inside as there is no door. Steps are normally available to facilitate this process.
Balloon baskets are comparatively small given typical lifting capacities and the pilot usually occupies the central area where the various controls are accessible. Passengers are normally spaced around the edge of the basket which is ideal for photography provided all the necessary equipment is within convenient reach.
When everything is ready the pilot flares the burners to increase lift and start the balloon rising. The ground crew releases the balloon, which may have been tethered to a recovery vehicle, and the flight is underway. No motion is felt as the balloon rises, and any wind drops away as the balloon begins moving with the air currents. In a comparatively short period passengers are surrounded by complete silence which is only occasionally shattered by the roar of the flaring burners. There may be wonderful opportunities for aerial photography.
As altitude increases, look out for shots of the receding ground crew, the shadow of the balloon passing over the terrain below, other balloons in the area - particularly those beneath you. In general, the best shots are obtained at lower altitudes, perhaps below 500 feet, although there are always exceptions. Higher up the shots become more hazy and ground-based features more distant.