Unfortunately, I’m your first comment and I’m going to disappoint a because I don’t have any specific recommendations. But I do have an idea.

If you’re looking for the Dan Browns and Stephen Kings of the Spanish and French languages, why not start with translations of those authors into those languages? This might be especially useful if you read a story that you’re already somewhat familiar with. A Spanish translation of “The Gunslinger” sounds like something I’d be interested in once my language skills improve.

Also, abridged versions of novels are often written with younger readers in mind, so an abridged version might be more accessible.

You’ve probably already done this and are looking for something more. I hope you get some better answers so I can check back here for recommendations too.

Airport thriller is a new concept to me so I’m not sure if these qualify:

Zafón’s La sombra del viento. A best-seller, quite dark and riveting with a Spanish Civil War background.

Teixidor’s El libro de las moscas. I don’t know if it was originally written in Catalan or in Spanish though. More mystery than thriller as far as I remember.

García-Márquez’s Crónica de una muerte anunciada. Absolute classics, both book and author.

Atxaga’s Obabakoak. Also more mystery than thriller. Also originally written in Basque, but the Spanish translation was done by the author himself.