The phrase "backup plane" is correct and usable in written English.
It is typically used to refer to a reserve plane that is ready to take flight in the event of an emergency. For example, "The small regional airport had a single backup plane in case of mechanical complications with their regularly scheduled flight."
Then they waited in the airport for a backup plane and watched on television as men walked on the moon.
For years, presidential travel has included at least two other aircraft: a backup plane and a military cargo plane to ferry Secret Service vehicles, helicopters on occasion and the president's customized limousine, nicknamed "the Beast".
He said that in August 1999, workers removed Strandflex engine control cable from a backup plane to Air Force 2. The F.A.A.'s account of how it handled the case raises as many questions as it answers.
How much it cost taxpayers to fly Air Force One and its backup plane, transport the armored presidential limousines across the ocean and provide security for the whirlwind trip was uncertain.
If a passenger arrived within five minutes of departure and was denied a seat, Delta would put the passenger on a backup plane within 15 minutes or provide a free one-way shuttle ticket.
In August 1999, Air Force mechanics replaced cable linked to the engine controls of a backup plane to Air Force Two, which is used by Vice President Al Gore.
If no backup planes are available, lines for later flights can stretch to hundreds of people when there is a gap of two hours between departures.
So, FedEx could not anticipate the need to send backup planes and trucks to Freeport, Me. -- some by circuitous routes, because the snowstorm wreaked havoc with Northeast airports and roads -- to handle the unexpectedly high volume that the bad weather generated for L.L. Bean, which is based there.
Backup planes for security and press?
While far fewer cancelations were reported at Midway airport, many Southwest Airlines passengers were stuck on the tarmac for up to four hours on Friday morning as a backup in plane traffic that started Thursday night caused arriving planes to land without having anywhere to go.
The only thing that went wrong was the breakdown of a backup press plane.
