Tiffany is an inhabitant of the city of Grancel.
She's a woman working at the royal city's landing port as an airship technician.
Things haven't been going extremely well at the airport, first with the Linde having been hijacked followed by the attack on Zeiss Central Factory and the resulting emergency measures taken by the army, which included security checks on all arriving and departing airships, causing massive delays.
She and her colleagues do their best to get the arriving ships ready as soon as they can, but the situation nevertheless leaves them annoyed. It gets even worse when military patrol ships started accompanying the airliners, forcing her and her colleagues to perform quick maintenance on them too. And after the martial arts tournament, the airliners are grounded altogether, causing her to fume at the army's actions.
Fortunately, the Intelligence Division's coup gets thwarted, leaving her to resume her work again and causing her to mention they'll have to work hard to continue being seen as a reliable company after all the issues with the air traffic lately.
After the Royal Guard was accused of treason, their flagship, the Arseille, was grounded in Grancel Airport and like other airport workers, Tiffany was greatly impressed with the state-of-the-art airship.
With the Birthday Celebration over, life at Grancel Airport returns to normal, which includes Tiffany getting irritated by Carnero, her superior, fumbling his duties resulting in a chewing out.
Tiffany is a very strong-willed person who's very passionate about her work and rather quick to get upset if something bothers her (such as Captain Amalthea's arrogant attitude). This is a big contrast with Carnero, the chief technician and leader of her team, whose meek personality and inability to stand up for himself infuriate her and cause her to wish for a more assertive person being in charge.