This is a list of countries (sovereign states) and territories without an airport.
Of the world's countries, only five European microstates have no airport within their boundaries, though all have at least one heliport. All, except for Monaco, are landlocked. (Liechtenstein is doubly landlocked.)
Of the world's 17 non-self-governing territories, two have no airport within their boundaries: Tokelau and the Pitcairn Islands. Both are remote island groups, so a fairly long boat trip is the only way to get there.