i suggest you re read it. here it is:
§61.159 Aeronautical experience: Airplane category rating.
(a) Except as provided in paragraphs (b), (c), and (d) of this section, a person who is applying for an airline transport pilot certificate with an airplane category and class rating must have at least 1,500 hours of total time as a pilot that includes at least:
(1) 500 hours of cross-country flight time.
(2) 100 hours of night flight time.
(3) 50 hours of flight time in the class of airplane for the rating sought. A maximum of 25 hours of training in a full flight simulator representing the class of airplane for the rating sought may be credited toward the flight time requirement of this paragraph if the training was accomplished as part of an approved training course in parts 121, 135, 141, or 142 of this chapter. A flight training device or aviation training device may not be used to satisfy this requirement.
(4) 75 hours of instrument flight time, in actual or simulated instrument conditions, subject to the following:
(i) Except as provided in paragraph (a)(4)(ii) of this section, an applicant may not receive credit for more than a total of 25 hours of simulated instrument time in a full flight simulator or flight training device.
(ii) A maximum of 50 hours of training in a full flight simulator or flight training device may be credited toward the instrument flight time requirements of paragraph (a)(4) of this section if the training was accomplished in a course conducted by a training center certificated under part 142 of this chapter.
(iii) Training in a full flight simulator or flight training device must be accomplished in a full flight simulator or flight training device, representing an airplane.
(5) 250 hours of flight time in an airplane as a pilot in command, or when serving as a required second in command flightcrew member performing the duties of pilot in command while under the supervision of a pilot in command, or any combination thereof, which includes at least—
(i) 100 hours of cross-country flight time; and
(ii) 25 hours of night flight time.
and from 61.1:
Cross-country time means—
(i) Except as provided in paragraphs (ii) through (vi) of this definition, time acquired during flight—
(A) Conducted by a person who holds a pilot certificate;
(B) Conducted in an aircraft;
(C) That includes a landing at a point other than the point of departure; and
(D) That involves the use of dead reckoning, pilotage, electronic navigation aids, radio aids, or other navigation systems to navigate to the landing point.
(ii) For the purpose of meeting the aeronautical experience requirements (except for a rotorcraft category rating), for a private pilot certificate (except for a powered parachute category rating), a commercial pilot certificate, or an instrument rating, or for the purpose of exercising recreational pilot privileges (except in a rotorcraft) under §61.101 (c), time acquired during a flight—
(A) Conducted in an appropriate aircraft;
(B) That includes a point of landing that was at least a straight-line distance of more than 50 nautical miles from the original point of departure; and
notice that ATP is not included in section ii, so section B does not apply.
61.1 is badly formatted but under the Cross-Country section is 61.1 (B) VI which is the applicable paragraph/portion for ATP. It states:
(vi) For the purpose of meeting the
aeronautical experience requirements for an airline transport pilot certificate (except with a
rotorcraft category rating), time acquired during a flight -
(A) Conducted in an appropriate
aircraft;
(B) That is at least a straight-line distance of more than 50 nautical miles from the original point of
departure; and
(C) That involves the use of dead reckoning,
pilotage, electronic navigation aids, radio aids, or other navigation systems.
Note the difference between 61.1 (B) VI for ATP and 61.1 (B) II for PPL/IRA/CPL which states:
(ii) For the purpose of meeting the
aeronautical experience requirements (except for a
rotorcraft category rating), for a private pilot certificate (except for a
powered parachute category rating), a commercial pilot certificate, or an
instrument rating, or for the purpose of exercising recreational pilot privileges (except in a rotorcraft) under
§ 61.101 (c), time acquired during a flight -
(A) Conducted in an appropriate
aircraft;
(B) That
includes a point of landing that was at least a straight-line distance of more than 50 nautical miles from the original point of
departure; and
(C) That involves the use of dead reckoning,
pilotage, electronic navigation aids, radio aids, or other navigation systems to navigate to the landing point.
It is also different from 61.1 (B) I which is the minimum definition of a cross-country and is the one applied to experience requirements under Part 135 and states:
(i) Except as provided in paragraphs (ii) through (vi) of this definition, time acquired during flight -
(A) Conducted by a
person who holds a pilot certificate;
(B) Conducted in an
aircraft;
(C) That includes a landing at a point other than the point of departure; and
(D) That involves the use of dead reckoning,
pilotage, electronic navigation aids, radio aids, or other navigation systems to navigate to the landing point.
61.1 (B) I requires a landing but does not require you to fly 50NM from your point of origin
61.1(B)VI does not require landing but does require you to fly at least 50 NM from your point of origin
61.1(B)II requires both a landing and the landing be 50NM from your point of origin.
The most common ways hours are accumulated under the ATP definition for this would be military flights, pipeline patrols, banner towing and site-seeing tours (Grand Canyon, Hudson SFRA, etc) but other scenarios also exist/are possible.
Note the definition applied under 61.1(B)VI towards an ATP currently matches the definition used for military pilots seeking a CPL under 61.1(B)VII.