The CASA C-101 Aviojet is a Spanish advanced trainer with light attack capability in the same category of other designs like the Hawk and Alpha Jet. It was designed with technical assistance from Northrop and MBB and is characterized by a conventional trainer configuration which has the novel feature of incorporating an internal weapons bay in addition to external stores; this bay can also store additional equipment such as reconnaissance cameras, ECM jammers, or laser designators. Initial Aviojet trainer versions were eventually complemented by dedicated attack variants most of which were geared for export to countries like Honduras, Jordan, and Chile (most of them partially built and assembled locally by ENAER). Besides their trainer and attack variants, the Aviojet is also famous for being used by the Spanish acrobatics team, the Patrulla Águila.

First flight of the original C-101EB trainer, known as the E.25 Mirlo (Blackbird) in Spanish service, took place on 27 June 1977 entering service at the turn of the decade. It was followed by the C-101BB combat-capable trainer export version sent to Honduras and Chile (produced locally and designated T-36 Halcón) and later the C-101CC dedicated light attack version for Jordan and Chile (also locally-built as the A-36). An enhanced variant with uprated engines, HUD, and new avionics and weapons was the C-101DD but has yet to obtain orders.