A new runway made to fit to the side of another runway and to fit at 45 degrees. Can be found under Lighting / Ceiling lights and costs 0. It's over 360 metres long. It has 20 strobe lights like runway 2. It's the same width as runway 2.
Where the plane is standing you need to build a new lot to place the new runway.
You need Late Night for it to show up.
NB. All these 3 runways can be used on an airport, if you have one.