Mil Engineer Not Building Airstrip

[MarechalLannes]

Hi all - I searched before I posted, but dodn't find anything. My engineer in in my territory on a flat grassland (no hills) and doesn't give me the build airstrip option. What am I missing? My city that controls the tile has a spaceport, but not an aerodrome or airport. It has 16 pop. I have extra oil resources too.

Any help appreciated

 

[Equilin]

a screenshot will be very helpful

 

[criZp]

It is an engineer right, not a builder?

 

[Tech Osen]

Is it a floodplain?

 

[Piranga]

I was having the same problem in a game I played over the last few days. Had the technology unlocked, couldn't build an airstrip anywhere.

 

[BomberEscort]

I should be able to build an air strip on a hill as well.

 

[tedhebert]

Has to be FLAT terrain, cannot be in enemy or City-State territory. I'd wonder if there's a hidden strategic where you wanted to build, but... you seem pretty advanced in the game, even Uranium should be researched...