Alitalia had a diverse fleet during the 1970s and 80s as it bought new aircraft to replace older types but then sold them on at quite a young age. In fact it had already passed up Airbuses new widebody A300 once in the mid-1970s only to come back round to the type in the late 70s. It would go on to be the mainstay of its high density short and medium haul routes for nearly 20 years.
The first A300B4 to join the Alitalia fleet was registered I-BUSB and all of the carrier's A300s would have suitably appropriate BUS registrations. BUSB joined in April 1980 and was followed in quick succession by I-BUSC, SD, SF, SG, SH, SJ and SL. The 8 remaining DC-8-62s had all left the fleet by 1982 with the last A300, I-BUSL, arriving in late February.
Alitalia was obviously content with its A300s, and in fact the airline also retired its DC-10s at about the same time - partly replaced by 747s and partly no doubt by the A300s. As the 1980s drew to a close Alitalia took the opportunity to add to the fleet when it purchased 6 former Eastern Air Lines aircraft. From September 1988 to March 1990 these frames took up the Italian registrations I-BUSM, SN, SP, SQ, SR and ST. Their arrival no doubt assisted to manage the increased traffic related to the Italia 90 Football World Cup.
Dienel, H & Lyth, P. Flying the Flag: European Commercial Air Transport since 1945
Sweetman, B. 1976, December. Alitalia climbs out with crossed fingers. Flight International
RZjets.net - Alitalia A300s