Looking back, it’s incredible to think that the cockpit was like a tourist attraction!
The company, that I work for had already designed and manufactured a fortified Kevlar bulletproof cockpit door, up until 9/11 we didn’t have many takers, as the doors fitted were previously made of tissue paper and very often pinned open.
Post 9/11 the doors became mandatory, and we spent the next 10 years retrofitting and installing bulletproof cockpit doors,with pin code access which are now fitted on all commercial aircraft.