Bats are able to fly dark without trouble because bats have a navigation system which works very similar to __:

SONAR
Bat echolocation is very much similar to a SONAR and is a perceptual system where ultrasonic sounds are emitted specifically to produce echoes. By comparing the outgoing pulse with the returning echoes, the brain and auditory nervous system can produce detailed images of the bat’s surroundings. This allows bats to detect, localize and even classify their prey in complete darkness. At 130 decibels in intensity, bat calls are some of the most intense, airborne animal sounds