A special bolt with an explosive charge built into it. The charge
is remotely activated, and causes the bolt to fail and release its
hold. Explosive bolts are used to allow stages of rockets to
separate, and also to release drop tanks from combat
"As other targets become hardened, the ones that are
softer could become more desirable targets."
Source: Martha's Vineyard Airport Manager Sean
Flynn. MVY is but one of several airports throughout the country
that have adapted new security procedures in the wake of last
weekend's botched terror attack at Glasgow Airport.