The SHIELD helicarrier: basically, it's an aircraft carrier with four gigantic VTOL engines attached near the corners.

Helicarrier below frontend

Helicarrier below

Helicarrier sideview

Helicarrier frontview

Helicarrier front closer

Helicarrier bridge closeup

Helicarrier bridge closeup 2

Helicarrier deck view

SHIELD logo

SHIELD badge