1)To call someone unattractive over for sex while keeping all your lights off (inside and out) so neither you nor your neighbors can see what they look like. Then once you'redone you hurry them out to keep your sexual encounter a secret.
2)Someone to have sex with too embaressing/ugly to let anyone see.
I was horny as hell and needed a "night flyer", so I called that toothless, forty-two year old woman from the bar to come over last night.
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.