MTL - Plane Development Plan - ~ Episode 7: Unlimited Lucky Degree

Offered as a bride to Hades at the age of eighteen.

Pestered by evil spirits in the day, and taken advantage of by a perverted demon at night.

Pervert: “Dear, a night with you is worth more than gold.”

I leaned away as I clenched my teeth angrily: “Worth my foot!”

- Description from Novelupdates

During the day, she was his secretary, working very hard with excellent abilities. At night, she was his bedmate, trying her best to please him, and the two of them were very harmonious in bed. One day, this relationship was on the verge of ending. However, both of them had already become deeply involved and had grown accustomed to each other's presence, falling in love with each other. So...

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”