C-17 vs C-5 Galaxy: Payload, Range and Mission Compared

April 4, 2026 by Jason Michael 9 min read

C-17 vs C-5 Galaxy Why the Air Force Needs Both

The C-5M Super Galaxy carries more weight and offers a much larger cargo compartment; the C-17 Globemaster III trades some capacity for a smaller crew, airdrop capability and access to shorter, narrower and more austere airfields. The Air Force keeps both because they solve different parts of the strategic-airlift problem.

This comparison uses current U.S. Air Force fact sheets. Runway, payload and range figures describe published reference conditions—not permission to plan a real mission without current approved data.

C-17 vs C-5 specifications

Specification	C-17 Globemaster III	C-5M Super Galaxy
Primary role	Cargo and troop transport; strategic delivery, tactical airlift and airdrop	Outsize strategic cargo transport
Maximum cargo	170,900 lb	281,001 lb
Pallet positions	18	36
Cargo-compartment length	88 ft	143 ft 9 in
Cargo-compartment width	18 ft	19 ft
Cargo-compartment height	12 ft 4 in	13 ft 6 in
Maximum takeoff weight	585,000 lb	840,000 lb
Published basic crew	3: pilot, copilot, loadmaster	7: pilot, copilot, two flight engineers, three loadmasters
Current USAF inventory	222 in April 2025 fact sheet	52 C-5B/C/M in Air Force fact sheet

Payload: the C-5M carries about 110,000 pounds more

The C-5M’s published maximum cargo load is 281,001 pounds, about 110,000 pounds more than the C-17’s 170,900-pound maximum payload. Its cargo compartment is also more than 55 feet longer and provides twice as many pallet positions.

That makes the C-5M the stronger choice when cargo weight, length or total volume exceeds the C-17’s envelope. Actual loadability still depends on dimensions, floor and axle loading, restraint, center of gravity and the route. A maximum-payload number alone never proves that a specific combination of vehicles fits.

Cargo access: two ends versus one

The C-5M can open both its nose and aft cargo doors. Full-width ramps allow simultaneous loading and unloading from both ends and support drive-through handling of long or oversized equipment.

The C-17 loads through a large aft ramp and door. Its floor converts between a flat surface for wheeled or tracked vehicles and rollers for pallets. The Air Force identifies the 69-ton M1 Abrams among the equipment the C-17 can accommodate, subject to qualified load planning.

Airfield access: the C-17’s defining advantage

The Air Force publishes a C-17 capability to take off and land on runways as short as 3,500 feet and 90 feet wide under the conditions behind that figure. High-lift devices, externally blown flaps and thrust reversers support short-field and austere operations. The aircraft can also back under its own power and use a three-point turn on a narrow runway.

The C-5M can operate from relatively short runways for an aircraft of its size, but its 247-foot length, 223-foot-class wingspan, 840,000-pound maximum takeoff weight and infrastructure needs make it a different airfield-planning problem. A dated GAO comparison used a 6,000-foot minimum reference for the C-5 versus 3,500 feet for the C-17. Real suitability depends on pavement strength, width, obstacles, weather, weight and current performance data.

Range: compare equal payload conditions

Range comparisons often become misleading because the payload assumptions differ. The Air Force lists these reference points:

C-17: approximately 2,400 nautical miles with a 164,900-pound payload and an initial cruise altitude of 28,000 feet.
C-5M: approximately 4,800 nautical miles with 120,000 pounds of cargo.
C-5M at 281,001 pounds: 2,150 nautical miles, followed by an offload and a further 500-nautical-mile flight without refueling.

Both aircraft can refuel in flight. Neither maximum range nor maximum payload should be quoted without the accompanying conditions.

Crew and ground-support footprint

The C-17’s basic crew is three. The C-5M fact sheet lists seven: a pilot, copilot, two flight engineers and three loadmasters. Missions can add personnel or augment crews, but the published basic crews show the design difference.

The C-5M’s greater size and two-end loading capability can move more cargo per sortie, while the C-17’s smaller crew and forward-field design can make it more flexible near the destination. The most efficient choice depends on cargo, airfield, schedule, support and onward-movement requirements—not a single “better aircraft” score.

Airdrop and personnel missions

The C-17 was designed for tactical airlift and airdrop as well as strategic delivery. The Air Force publishes capacity for 102 troops or paratroopers and identifies airdrop as a core mission.

The C-5M fact sheet defines its primary function as outsize cargo transport. Its strength is moving very large loads over intercontinental distances, not replacing the C-17’s combination of strategic lift, airdrop and austere-field access.

Which aircraft should a mission use?

Mission need	Usually favors	Why
Heaviest or longest outsize cargo	C-5M	281,001-lb maximum cargo and much longer compartment
Twice the pallet positions	C-5M	36 versus 18
Short, narrow or austere destination	C-17	Published 3,500-by-90-foot capability and backing
Paratroop or cargo airdrop	C-17	Airdrop is a core published mission
Drive-through cargo handling	C-5M	Opening nose and aft doors

Why the Air Force still needs both

The C-5M concentrates extraordinary capacity in each sortie. The C-17 provides less capacity but reaches a wider range of airfields and performs missions such as airdrop. In a deployment network, C-5Ms can move the largest loads between major hubs while C-17s can deliver substantial cargo farther forward. The exact routing is a planning decision, not a rigid rule.

Air Mobility Command stated in 2026 that Next Generation Airlift will eventually replace the aging C-5M and C-17 fleets. Until that capability is defined, acquired and fielded, the existing aircraft remain complementary rather than interchangeable.

For more detail, see the C-17 cargo-capacity guide, the official C-17 operating-cost rates, and the distinct C-5 vs C-17 vs C-130 comparison.

C-17 vs C-5 FAQ

Which carries more cargo?

The C-5M. Its published maximum cargo load is 281,001 pounds versus 170,900 pounds for the C-17.

Which has the larger cargo hold?

The C-5M. Its compartment is 143 feet 9 inches long, 19 feet wide and 13 feet 6 inches high. The C-17 compartment is 88 feet long, 18 feet wide and 12 feet 4 inches high.

Can both carry an M1 Abrams tank?

The Air Force fact sheets identify the M1 Abrams as transportable by both aircraft. The C-5M has much greater maximum cargo capacity, but every actual load requires current qualified planning.

Why not replace every C-5M mission with C-17s?

Some cargo is too heavy, long or voluminous for a C-17, and using multiple smaller sorties can reduce efficiency. Conversely, the C-17 can reach airfields and perform airdrop missions that define a different operational niche.

Official sources

Jason Michael

Author

Jason Michael, an ATP-rated pilot who flies the C-17 for the U.S. Air Force, is the editor of C-17 Pilot. Articles on the site are researched, fact-checked, and reviewed before publication. Read our editorial standards or send a correction at the editorial policy page.