LAN Airlines’ latest fleet plan reduces its 2012 Boeing 787 deliveries to just two aircraft and defers three 787s previously expected for this year to 2014.

The carrier also revised its Boeing 767 delivery schedule, with two additional 767s added to an established delivery schedule that expected five deliveries in 2012 and two more in 2013.

No explanation for these changes to the 787 or 767 fleet plans is being given by the airline and Boeing has a policy of not commenting on specific airline delivery schedules. The previous delivery schedule remained unchanged in LAN’s second and third quarter results presentations.

LAN’s new fleet plan also includes an additional Airbus narrowbody delivery for both 2012 and 2013 compared to a plan issued for the operator’s third quarter financial results. Net single aisle deliveries are now expected to reach eight and 10 aircraft, respectively, in 2012 and 2013.

These two aircraft appear to be taken from 2014 slots, with 15 aircraft from Airbus’ A320 family now expected to be added to the fleet in that year.

During the company’s fourth quarter call today, management also confirmed that three Boeing 737-700s leased by its recently rebranded LAN Colombia operation will be replaced by A320s this year. LAN also plans to reduce its A318 fleet by five aircraft in 2012 and return two leased 767-300s to their lessors.

Two Boeing 777 freighters being added to LAN Cargo’s inventory are expected in the second half of the year, the carrier added.

Apart from the fleet changes, LAN’s management also indicated that the merger with Brazilian operator Grupo TAM, while still expected to be completed by the end of the first quarter, may now slip into the first week of April. Regardless, consolidation is still expected to start in the second quarter, with synergies implemented from May, unless a legal challenge delays the merger, said CFO Alejandro de la Fuente.

The leadership team also affirmed that it will not make an airline alliance decision for at least six months after completing the merger with TAM, and that yesterday’s announcement by American Airlines that the Chilean carrier was relocating to its Terminal 8 at New York’s John F. Kennedy International Airport was unrelated.

Regulators in Brazil and Chile have demanded that LAN and TAM choose a single alliance for the entity that will be created by their merger. LAN is an established member of Oneworld; TAM joined Star Alliance in 2010.

Apart from the merger, this year will mark another period of double digit growth for LAN, with passenger capacity expected to increase 12-14% (in line with the 13.7% rise in available seat kilometers), on a strong demand that boosted passenger revenues 28.9% last year. Operating expense, though, will continue to be pressured by fuel costs as they were in 2011, when fuel expense rose 46.7% year-on-year.

That rise in fuel costs, combined with the adverse effects of volcanic ash clouds and the integration of LAN Colombia, increased total operating expenses 32.8% in 2011, which in turn depressed operating income 13.4% to $539.7 million and LAN’s operating margin by 4.3 percentage points to 9.4%. Net income fell 23.7% in 2011 to $320.2 million.