When Naval Lt. Bill Gardner (Nicolas Lea) first meets Lena (Allison Hossack) in the diner, he tries to pay for his coffee with a vintage silver certificate 5 dollar bill (1923 series), known as a "porthole". It is a rare 5 dollar note and is actually worth hundreds of dollars in today's money due to it's collectible status. Lena's character apparently knows that silver certificate notes are far more valuable than their face value, which is why she questions him if he's sure that he want's to use that vintage money to pay for his coffee.
Setting up for a sequel? At the end of the movie, when the portal back to 1943 opens up, a stealth bomber is also pulled into the portal. In Philadelphia Experiment 2 (1993) a stealth aircraft ends up in 1943 in German hands.
Near the end of the movie, when the Dr. Falkner is describing controls to Bill Gardner, he calls one a "Magnetic Flux Capacitor", perhaps as a nod to the Back to the Future movies, which are also about time travel.
Ryan Robbins (Richard Falkner) guest starred in the Canadian sci-fi series Continuum, where he played Brad Tonkin , a soldier from the future. Nicholas Lea (Bill Gardiner) also guest starred in the series as Agent Gardiner, a CSIS (Canadian intelligence) investigator.