While at Edward Fyers' base, a radio transmission is heard that identifies "Ferris Air Flight". Farris Aircraft, Inc. is the aircraft developer that Hal Jordan once worked for in the DC Universe... The same universe in which Hal Jordan is the Green Lantern, who is long time friend and teammate of the Green Arrow.
Three times in the series the 22nd episode shares a title with a Bruce Springsteen song; This Is Your Sword (2015) is from the album High Hopes. Darkness on the Edge of Town (2013), and Streets of Fire (2014). Both are from the album Darkness on the Edge of Town.
When Oliver and Tommy meet, there is a reference, whether intended or accidental, to Batman: The Dark Knight - "Why so serious?".
In the DC Universe, Brion Markov is Prince of Markovia. He is also the hero Geo-Force.
The title is likely a reference to the Bruce Springsteen song. This is the case for the penultimate episode of every season except the final one (which was originally intended to be a Bruce Springsteen song, but was changed before airing).