After Rebirth, the Miracle Doctor Wife Is No Longer Humble! - Chapter 34: Nightmare

The story revolves around Charles Karino, a Levaamu Empire mercenary aerial pilot who mans the twin seater reconnaissance seaplane Santa Cruz. One day, he receives a preposterous assignment: to fly solo over 12,000 kilometers of enemy waters to protect a girl named Fana del Moral. Fana happens to be the next in line to the empire’s throne and a girl possessing beauty “equal to 5,000 beams of light.”

This is a standalone book. There’s another series under the name “To Aru Hikuushi e no Koiuta” (Love Song for a Certain Pilot) set in the same world, but in a completely different place and with different characters.

– Ulrezaj @ Mazui

Adapted to anime as “The Princess and the Pilot”

This is the story of Kir, who has to thwart the will of Heaven, Hell, and his parents in order to survive, protect the people he loves, and achieve happiness.He just has to make it through life at a magical academy, avoid dying, and survive to find his birth mother, the lost Daughter of Heaven. Or be forced to take his place at the side of his father, a Duke of Hell bent on destroying the way things are.It's a lot to handle for a quiet, brooding angel boy.Fortunately, he has company. A succubus, a foxkin girl, and a half-angel boy to start. And Kir has his own secret: this isn't his first go at life.

Accidentally, she got pregnant.

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates