A bazooka is a single shot man-portable device like this
http://www.rt66.com/~korteng/SmallArms/bazooka.htm , whilst a rocket-launcher is multiple-shot device mounted on an aircraft or vehicle like this
http://acam.ednet.ns.ca/weapons/CRV7.htm .
I should mention however, that getting either of these approved for civil aircraft use in the UK, is probably beyond even my powers of professional persuasion.
Cheers,
G