Most people do not parachute on purpose from jet aircraft. The planes are too fast, and the turbulent air dragging in their wake can snap your spine and pop your hips from your pelvis. We were trained to jump from commercial airliners because they are ubiquitous and nonattributable. It is one thing to prohibit American military aircraft from flying over your country. It is quite another to close down your airspace to all commercial traffic. Libya, Syria, Cuba, and a host of other thug nations allow commercial flights to fly through their airspace. This is all the opening a SEAL Team needs. Unknown and unseen, a SEAL element can parachute into any place on earth. One might insert: that is, provided one survives the jump. The trick is to exit in correct body position and deploy your parachute after the appropriate delay. There are two principal types of SEAL parachute operations: HALO, or high altitude, low opening; and HAHO, high altitude, high opening.
In a HALO drop, you exit the aircraft at 35,000 feet on oxygen and open your parachute low, at 2,000 feet, to avoid detection. A jumper falling at terminal velocity, roughly 120 miles an hour, would scream in for a full three minutes before opening his parachute.
In a HAHO drop, jumpers exit the aircraft above 35,000 feet, but their parachutes are deployed after a brief delay, maybe three seconds, opening high instead of low-sometimes literally in the jet stream. The team floats under canopy at 33,000 feet, then groups together and glides in formation toward the target.
