Again try to keep perches at opposite ends of the flight to encourage flying. If at all possible add a safety porch or mantrap to your outdoor aviary. This is an area you must enter and close off before entering the aviary. If a bird escapes it only goes into the porch and is not lost to the outdoors. If this is not possible, build the doors as low as possible, even if you must crouch to enter.
Doves tend to fly upward to escape.
Low doors will reduce the loss of birds. The door can be located at the shelter if needed, however the safety trap is most important, as the birds cannot be seen before opening the door. If the flight is planted, be sure the plants are safe for the birds and keep them trimmed to allow movement and flight. Place nests in the upper third of the shelter or if placed in the flight, be sure the nests are protected from the elements. Food and water area should be protected from being fouled by birds or weather.