Flight profile · Delta Air Lines

DL639

Los Angeles (LAX) to Boston (BOS) · scheduled 7:55 AM – 4:17 PM

FlyerIntel does not track flights in the air. This page describes how DL639 has historically performed, which is a different and more useful question when you are deciding what to book. For today’s status, check with Delta Air Lines.

How DL639 performs

559 operations, 2024-12-19 to 2026-06-30.

On-time arrivals
84.6%
466 of 551 completed
Cancellation rate
1.43%
8 cancelled
Median arrival delay
-6 min
Average 2.4 min
Severe delays
4.4%
Arrived 60+ minutes late
Delay when late
71 min
Average, when 15+ min late
Departure punctuality
90.2%
Left the gate on time

DL639 arrived on time 84.6% of the time, against 80.5% for all LAXBOS flights — this specific departure is 4.1 percentage points better than the route as a whole. Against Delta Air Lines’s own flights on this route it is 3.5 points better.

Source: US DOT Bureau of Transportation Statistics · 559 operations between 2024-12-19 to 2026-06-30

Against the rest of the route

On timeCancelledMedian delaySevereFlights
DL63984.6%1.43%-6 min4.4%559
Delta Air Lines on LAXBOS81.0%0.83%-7 min6.7%3,494
All LAXBOS flights80.5%0.74%-8 min7.2%13,840

Source: FlyerIntel analysis of US DOT BTS data · 2024-12-19 to 2026-06-30

Other routes DL639 has flown

A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.

RouteOperatedFlightsOn time
LASATL Las Vegas to Atlanta2024-11-112024-12-1836
PDXATL Portland to Atlanta2024-10-072024-10-2519
ATLDEN Atlanta to Denver2024-09-092024-10-0628
DENATL Denver to Atlanta2024-09-092024-10-0628
LGAMCI New York to Kansas City2024-08-112024-09-0826
MCILGA Kansas City to New York2024-09-082024-09-081
DTWLAX Detroit to Los Angeles2024-07-132024-08-246
IADSEA Washington to Seattle2023-09-052024-06-0611579.3%
SLCSEA Salt Lake City to Seattle2024-04-112024-05-0616
ORFATL Norfolk to Atlanta2024-03-102024-04-0830
ATLHOU Atlanta to Houston2023-12-162023-12-3013
HOUATL Houston to Atlanta2023-12-162023-12-3013
MCOMIA Orlando to Miami2023-12-072023-12-159
MIAMCO Miami to Orlando2023-12-072023-12-159
LAXATL Los Angeles to Atlanta2023-07-012023-09-0466

Because the same number has served different journeys, the statistics above describe only the route DL639 currently operates. Blending them would produce an average of two different flights.

Data and methodology

Calculated by FlyerIntel from 559 records of DL639 operating LAXBOS, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.

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