land, sea and air
Refers to the three physical domains, often in contexts like transportation, geography, or general capability.
The transportation network across land, sea, and air is well-developed.
army, navy and air force
Specifically the three branches of the military; often used in compounds like 陸海空軍.
See also: 陸海空軍
The army, navy, and air force self-defense units were dispatched for disaster relief.