Delta Air Lines Inc. (DAL)

The following table summarizes Delta's property and equipment:

	Estimated Useful Life
Flight equipment	20-32 years
Ground property and equipment	3-40 years
Flight and ground equipment under capital leases	Shorter of lease term or estimated useful life

Delta records property and equipment at cost and depreciates or amortizes these assets on a straight-line basis to their estimated residual values over their estimated useful lives. The estimated useful life for leasehold improvements is the shorter of lease term or estimated useful life. Depreciation and amortization expense related to Delta's property and equipment was $2.2 billion, $1.9 billion and $1.8 billion for each of the years ended December 31, 2017, 2016 and 2015, respectively. Residual values for owned aircraft, engines, spare parts and simulators are generally 5% to 10% of cost.

Source: 10-K (filing date: 2018-02-23).

Delta Air Lines Inc., Statement of Financial Position, Property, Plant and Equipment

USD $ in millions

Based on: 10-K (filing date: 2018-02-23), 10-K (filing date: 2017-02-13), 10-K (filing date: 2016-02-05), 10-K (filing date: 2015-02-11), 10-K (filing date: 2014-02-24).

Item	Description	The company
Property and equipment, gross	Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.	Delta Air Lines Inc.'s property and equipment, gross increased from 2015 to 2016 and from 2016 to 2017.
Property and equipment, net	Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.	Delta Air Lines Inc.'s property and equipment, net increased from 2015 to 2016 and from 2016 to 2017.

Delta Air Lines Inc., Property, Plant and Equipment Ratios

Based on: 10-K (filing date: 2018-02-23), 10-K (filing date: 2017-02-13), 10-K (filing date: 2016-02-05), 10-K (filing date: 2015-02-11), 10-K (filing date: 2014-02-24).

Ratio	Description	The company
Average age	As long as straight-line depreciation is used, this is an accurate estimate of asset age as a percentage of depreciable life. The relative age is a useful measure of whether the company's fixed asset base is old or new. Newer assets are likely to be more efficient.	Delta Air Lines Inc.'s average age of depreciable property, plant and equipment deteriorated from 2015 to 2016 and from 2016 to 2017.
Estimated total useful life	Over longer time periods, this ratio is a useful measure of company's depreciation policy and can be used for comparisons with competitors.	Delta Air Lines Inc.'s estimated total useful life of depreciable property, plant and equipment increased from 2015 to 2016 but then declined significantly from 2016 to 2017.
Estimated time elapsed since purchase	The approximate age in years of a company's fixed assets. Useful for comparison purposes.	Delta Air Lines Inc.'s estimated time elapsed since purchase of depreciable property, plant and equipment deteriorated from 2015 to 2016 but then slightly improved from 2016 to 2017.
Estimated remaining life		Delta Air Lines Inc.'s estimated remaining life of depreciable property, plant and equipment increased from 2015 to 2016 but then declined significantly from 2016 to 2017.

Based on: 10-K (filing date: 2018-02-23), 10-K (filing date: 2017-02-13), 10-K (filing date: 2016-02-05), 10-K (filing date: 2015-02-11), 10-K (filing date: 2014-02-24).

2017 Calculations

Ratio	Description	The company
Average age	As long as straight-line depreciation is used, this is an accurate estimate of asset age as a percentage of depreciable life. The relative age is a useful measure of whether the company's fixed asset base is old or new. Newer assets are likely to be more efficient.	Delta Air Lines Inc.'s average age of depreciable property, plant and equipment deteriorated from 2015 to 2016 and from 2016 to 2017.

Based on: 10-K (filing date: 2018-02-23), 10-K (filing date: 2017-02-13), 10-K (filing date: 2016-02-05), 10-K (filing date: 2015-02-11), 10-K (filing date: 2014-02-24).

2017 Calculations

Ratio	Description	The company
Estimated total useful life	Over longer time periods, this ratio is a useful measure of company's depreciation policy and can be used for comparisons with competitors.	Delta Air Lines Inc.'s estimated total useful life of depreciable property, plant and equipment increased from 2015 to 2016 but then declined significantly from 2016 to 2017.

Based on: 10-K (filing date: 2018-02-23), 10-K (filing date: 2017-02-13), 10-K (filing date: 2016-02-05), 10-K (filing date: 2015-02-11), 10-K (filing date: 2014-02-24).

2017 Calculations

Ratio	Description	The company
Estimated time elapsed since purchase	The approximate age in years of a company's fixed assets. Useful for comparison purposes.	Delta Air Lines Inc.'s estimated time elapsed since purchase of depreciable property, plant and equipment deteriorated from 2015 to 2016 but then slightly improved from 2016 to 2017.

Based on: 10-K (filing date: 2018-02-23), 10-K (filing date: 2017-02-13), 10-K (filing date: 2016-02-05), 10-K (filing date: 2015-02-11), 10-K (filing date: 2014-02-24).

2017 Calculations

Ratio	Description	The company
Estimated remaining life		Delta Air Lines Inc.'s estimated remaining life of depreciable property, plant and equipment increased from 2015 to 2016 but then declined significantly from 2016 to 2017.