keeping in mind that EVERY commercial Passenger Jet will leave a "Contrail" or Condensation Trail which is nothing more than ice which forms after the very hot exhaust gas is expelled from the turbine engine. The Trail you have to watch for will happen above 45,000 feet and will appear from literally nothing in the form a faint rainbow. These are military aircraft flying in what is known as "Alpha Air" which is above 45K in altitude. Commercial Jets usually fly in the 32,000 to 43,000 feet range. Above 45 is "Military" airspace.
Good luck, I truly hope that you don't see the rainbow... Mitch