The Return Line is a gameplay element featured in various Ace Combat games, most notably in Ace Combat 04: Shattered Skies. It allows the player to rearm their plane if the player is running low on ammo, as well as repair the player's damage on easier difficulties.
First introduced in Ace Combat 04, the Return Line represents the boundary between the combat area and the player's "base". When a player crosses over this white, dotted line on the map (usually on the southern edge of the combat zone), they will engage in a landing minigame, either on a base runway or on an aircraft carrier, depending on whether or not the player's aircraft is carrier-based.
After successfully landing, the player has the option of changing the aircraft's special weapons (and will have their aircraft's damage completely repaired on easier difficulties), and then will be required to take off and return to the battle after reaching a certain altitude. The player will then spawn at the exact spot where they crossed over the Return Line.
In many games since its inception in Ace Combat 04, the Return Line appears as mission-critical. This means that, to complete the mission objectives, the player must cross over the Return Line at some point.
The Return Line appears in every mission in Ace Combat 04 at the player's disposal to cross over at any time. Some missions, such as Invincible Fleet and Whiskey Corridor, last for a long time and end up forcing the player to use the Return Line if they want to gain more points.
The Return Line is mission-critical in the following three missions: The Northern Eye, Lifeline, and Deep Strike. In each of those missions, the Mission Update requires that the player crosses over the Return Line to complete the mission (in the first, arbitrarily; in the second, to escape Yellow Squadron; in the third, to escape Stonehenge's attack).
The Return Line is also part of, but not mission-critical in, two other missions, namely Escort and Breaking Arrows. In Escort, the mission will be automatically accomplished if the civilian aircraft cross the Return Line. In Breaking Arrows, the mission will end in failure if any of the cruise missiles cross the Return Line.
The Return Line appears in only two missions in Ace Combat 5, and in neither appearance does it allow the player to rearm their plane.
Its first appearance is in the mission 8492. To complete the mission, the player can choose to either cross the Return Line or shoot down all of the enemy aircraft.
Its second and last appearance is in the mission Solitaire. Here, it is mission-critical during the Mission Update. The player must escape the enemy aircraft in pursuit by crossing over the line.
The Return Line appears once again in Ace Combat Zero. It appears in fewer missions than it does in Ace Combat 04, but it does allow the player to rearm in at least one mission, in contrast to Ace Combat 5.
The Return Line's appearances in Ace Combat 6 are akin to Ace Combat Zero in which it appears non-critical only in certain missions.
The Return Line is mission-critical in Invasion of Gracemeria, in which the player must retreat from the combat area. This does not apply to the Ace of Aces difficulty, where the Return Line doesn't exist at all.
The Return Line returns in Ace Combat 7 as an optional, non-critical point of resupply.
It appears in Long Day, Fleet Destruction, Anchorhead Raid, and Battle for Farbanti. In all four missions, the player can repair aircraft and/or switch special weapons, before taking off from there to continue with the mission.
There is a special case of the Return Line's appearance in Anchorhead Raid where there are three Return Lines as opposed to the usual one.
- In Lifeline, the Return Line actually shifts further south during the Mission Update.
- The Return Line does not always appear on the south of the combat zone. It is on the east in 8492 and Long Day, on the west in Lying in Deceit, and on the north in Battle for Farbanti.
- Ace Combat 04 is the only Ace Combat game where the Return Line appears in every mission.
- In Ace Combat 04, the position of the Return Line in correspondence with the map differs greatly. In some missions, it divides the combat zone almost in half.
- AWACS SkyEye gives a lengthy explanation of the Return Line in The Northern Eye:
- Use the return line on the map to exit combat area and return to base. Fly in the right direction, and you'll see a white dotted line across your flight path. Those of you who need to resupply or refuel during missions should cross this line to exit the combat area and return to base or carrier.
- Cut dialogue from Ace Combat 5 has Thunderhead explaining that the Return Line can be used for resupplying, indicating that the player was able to rearm in some missions. The reason for cutting this feature is unknown.