Methods include plastic-coated windows, energy-absorbing materials and tying down heavy objects and ceiling panels.

BBC: Newcastle engineers research bomb-proof train carriages

Defence firm Qinetiq and turbine manufacturing firm Vestas are developing "stealth turbines", with radar-absorbing materials and coatings.

BBC: 'Stealth' wind turbine deployed

Ceradyne also sells neutron-absorbing materials that can be used for nuclear fuel storage.

FORBES: Magazine Article

The B-1B has some stealth features: A smooth design and the use of radar-absorbing materials gave it an appearance on radar that is said to be only 1% of that of the older B-52 bomber, even though it is only a little shorter - at 146 feet (44.5 metres) - and weighs almost the same.

BBC: Profile: B-1 bomber