For decades Taiwan has designed sections of its highways to be converted to military runways in the event of an attack by China. Here's a review with photos of a training exercise a few years ago:
The [Taiwan] Air Force sent four types of aircraft to participate in the exercise: a F-16V Fighting Falcon, a Mirage 2000-5 multi-role fighter jet, and Taiwan’s own Indigenous Defense Fighter. The jets took off and landed with weapons onboard—the F-16 carried two Harpoon anti-ship missiles, two AMRAAM medium-range air-to-air missiles, and two AIM-9 Sidewinder short-range air-to-air missiles. The same jet or another jet later landed on the improvised airstrip, minus the two Harpoon missiles.
Surely other countries have similar provisions in place, considering some of the first military facilities to be taken out in the event of a surprise attack are military runways.
I was about to mention what I heard many years ago about 1 mile in every 5 of US highways having to be straight, so that in emergencies it could be used as a runway, but I decided to google it first for a reference and it turns out it's an urban legend:
https://www.fhwa.dot.gov/publications/publicroads/00mayjun/o...
I'm sure there are enough straight stretches that it could be done anyway. Seems that the Swedes practice on their highways with their Gripens regularly:
Yeah, in the Czech Republic (or especially the former Czechoslovakia), part of the main D1 highway (Prague-Brno) is designed as an alternate airfield.
Here is a (then-classified) 1980 army documentary about a large exercise on the highway (using MiG-21 and MiG-23 planes): https://www.youtube.com/watch?v=FDoZGoaG9_w (sorry, Czech only)
I wonder how they handle the support? It's not much use to land and take off warplanes if you can't also transport, load, and service weapons and also refuel the planes and fix any mechanical issues.
In Finland there are many roads that are extended and maintained as alternative "airfields", mainly for purposes of national defense but also as emergency landing sites for civilian craft
A taxi driver in Singapore told me that the highway in Singapore is also designed for planes to land on. My own observations indicated that this was plausible.
If by highway he meant the section of the East Coast Parkway that is straight and wide (the median has potted plants rather than planted trees), my recollection is that this is a myth, that section of the highway may have been intended for planes to land on in an emergency, but no longer. Unfortunately I do not have sources.
But if by highway he meant Lim Chu Kang road, then it's not just plausible: Lim Chu Kang road is actually used as an extra airstrip. The RSAF conducts regular exercises to ensure it can still be used as such, the last one being about 5 years ago [0]. There is an interesting video from 2009 on the subject too [1].
The [Taiwan] Air Force sent four types of aircraft to participate in the exercise: a F-16V Fighting Falcon, a Mirage 2000-5 multi-role fighter jet, and Taiwan’s own Indigenous Defense Fighter. The jets took off and landed with weapons onboard—the F-16 carried two Harpoon anti-ship missiles, two AMRAAM medium-range air-to-air missiles, and two AIM-9 Sidewinder short-range air-to-air missiles. The same jet or another jet later landed on the improvised airstrip, minus the two Harpoon missiles.
https://www.popularmechanics.com/military/aviation/a27633093...
Surely other countries have similar provisions in place, considering some of the first military facilities to be taken out in the event of a surprise attack are military runways.