Boeing 737-400

Narrow-body jet

BoeingPowered by CFM International or GE Aerospace
Busiest US routes for Boeing 737-400, by departures: HAV–MIA, MIA–SNU, CMW–MIA, HOG–MIA, CAP–MIA, MIA–SCU, HAV–RSW, AUS–CVG, CVG–PHL, PUJ–SJU, CID–CVG, CVG–STL, CID–MCI, RSW–SNUMIAHAVSNUCMWCVGHOGCAPRSWSCU
The busiest US routes for the Boeing 737-400, by departures — line weight is departures flown, dots are the airports it connects. Great-circle paths from US DOT T-100, trailing 12 months through May 2026.
Passengers flown a year
250.3K
44th-most common US type
Airframes in US fleets
21
US operators
4
Airports served
16
Countries
3
Load factor
30.0%

Where the Boeing 737-400 flies

Filed traffic data

The operators table below counts the registered Boeing 737-400 airframes each airline owns (US DOT Form 41). These figures are how much the type actually flew — departures, seats, and passengers filed with US DOT T-100 over the trailing 12 months, not fleet size.

Departures flown

6,701

May 2026

Seats flown

887,794

Passengers

250,290

Load factor

30.0%

RPM ÷ ASM

Block hours

10,547

Busiest Boeing 737-400 routes

The Boeing 737-400's busiest US routes over the trailing 12 months, by departures.

The longest and shortest Boeing 737-400 flights

The two ends of the type's working envelope, from the routes it actually flew — not what the airframe is certified to do.

Longest route flown

958 mi

Austin – Cincinnati / Covington (AUS–CVG)

2h 42m block · 139 departures

Flown by Kalitta Charters II.

Shortest route flown

228 mi

Miami – Santa Clara (MIA–SNU)

1h 15m block · 1,198 departures · 28% load

Flown by Eastern Air Express. Also one of the type's busiest routes anywhere in the US — a short hop worked like a bus line.

Source: US DOT Bureau of Transportation Statistics, T-100 Segment. Data through May 2026.

Airports the Boeing 737-400 serves

The Boeing 737-400 serves 16 US airports across 3 countries. The busiest, by departures:

  • MIA

    Miami

    2,338 departures · 6 routes · 1 operator

    42.4%

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  • HAV

    Havana

    1,103 departures · 2 routes · 1 operator

    20.0%

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  • SNU

    Santa Clara

    600 departures · 1 route · 1 operator

    10.9%

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  • CMW

    Camaguey

    228 departures · 1 route · 1 operator

    4.1%

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  • HOG

    Holguin

    197 departures · 1 route · 1 operator

    3.6%

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  • CVG

    Cincinnati / Covington

    196 departures · 3 routes · 2 operators

    3.6%

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  • CAP

    Cap Haitien

    178 departures · 1 route · 1 operator

    3.2%

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  • SCU

    Santiago

    130 departures · 1 route · 1 operator

    2.4%

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  • RSW

    Fort Myers

    103 departures · 1 route · 1 operator

    1.9%

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  • STL

    St Louis

    83 departures · 2 routes · 2 operators

    1.5%

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Browse all airports →

Who flies the Boeing 737-400

Two questions in one table. Airframes is what each carrier reported owning in its US DOT fleet filing; seats flown is how much of the type it actually operated. They can rank differently, and the gap is the interesting part.

Operator
Eastern Air Express37Q8887.8K100.0%23.7 yr
Kalitta Charters IIKLQ700.0%8.9 yr
Northern Air CargoNC5——11.6 yr
Aloha Air CargoKH1——1.0 yr

Airframes are the latest Form 41 filing; seats flown and share are US DOT T-100 for the type's most-flown operators — a dash means a carrier isn't among them (a freighter operator, or one that flies fewer).

How old is the US Boeing 737-400 fleet?

Boeing 737-400 — airframes by age (years)

Age is measured from each airframe's delivery date — the FAA airworthiness date where available, otherwise the manufacturer's. Bars share a fixed scale across every fleet page, so two carriers can be compared directly.

Oldest airframeN804TJBoeing 737-40037.3 yr · Delivered May 11, 1989
Newest airframeN440KHBoeing 737-4001.0 yr · Delivered Sep 5, 2025

Monthly Boeing 737-400 capacity

553
695
953
746
447
495
544
492
445
460
482
389
JunJulAugSepOctNovDecJanFebMarAprMay
Monthly Boeing 737-400 departures across US routes, trailing 12 months through May 2026. Peak month in solid ink.

How common is the Boeing 737-400?

The Boeing 737-400 makes up 0.2% of all tracked US airline aircraft — the 44th-most common type in service.

Share of all tracked US airline aircraft · top 12 types shown · 118 others hold the remaining 37.4% · Boeing 737-400 is the ringed slice at 0.2%

Frequently asked

How many Boeing 737-400 are in US airline fleets?

US carriers operate about 21 Boeing 737-400 aircraft across 4 airlines, 20 of them in service.

Which airline operates the most Boeing 737-400?

Eastern Air Express operates the largest US Boeing 737-400 fleet, with about 8 aircraft.

What is the busiest Boeing 737-400 route?

The busiest US route flown by the Boeing 737-400 is HAV–MIA, with about 2,007 departures over the trailing 12 months.

Which airline flies the Boeing 737-400 the most?

Eastern Air Express flies the most Boeing 737-400 capacity in US service, with about 887.8K seats flown over the trailing 12 months.

How many passengers does the Boeing 737-400 carry?

The Boeing 737-400 carried about 250.3K passengers on US routes over the trailing 12 months.

What is the longest Boeing 737-400 flight?

The longest US route flown by the Boeing 737-400 is AUS–CVG, about 958 miles, flown by Kalitta Charters II.

How many airports does the Boeing 737-400 serve?

The Boeing 737-400 serves about 16 US airports across 3 countries, led by Miami (MIA).

How old is the average Boeing 737-400?

The US Boeing 737-400 fleet averages about 14.8 yr.

How common is the Boeing 737-400 in US fleets?

The Boeing 737-400 is the 44th-most common aircraft type in tracked US airline fleets, by number of aircraft.

Inventory: US DOT Form 41 Schedule B-43 (2025). Deliveries: Airbus & Boeing official reports. Registry status: FAA. Last refreshed Aug 1, 2026.