One of the aircraft deals that will be watched most closely this year will be All Nippon Airways' intended Boeing 777 replacement order.

Not only will its potential size make it significant, but it is also seen as a competition Boeing badly wants to win following Japan Airlines' (JAL) decision last year to order Airbus widebodies as eventual replacements for its own 777 fleet.

Japan traditionally has been something of a Boeing stronghold, and the manufacturer has extensive industrial ties in that country. However, JAL leadership had been signaling before the order that it wanted to reduce its reliance on a single airframe manufacturer. Boeing still has sizable orders in Japan through its 787 program, but if All Nippon Airways (ANA) follows JAL with a major widebody order, it would be seen as a blow for the U.S. manufacturer.

ANA has previously confirmed that it is considering the Boeing 777X or the Airbus A350 to replace its existing 777 fleet. It has signaled that a decision may come soon, although it has not revealed a target date.

The carrier intends to begin replacing its 777s in about 2020. It currently operates 54 777s, including -200s, -200ERs, -300s and -300ERs. ANA says it will first look to replace the 25 777s used on international routes.

JAL's order encompasses up to 56 aircraft. This includes firm orders for 18 A350-900s and 13 A350-1000s, with options for a further 25 aircraft.

The airline operates a fleet of 46 777s, with -200s and -300s primarily used in its domestic fleet, and -200ERs and -300ERs for international routes. The A350s will replace both fleets.

This year will also be significant for ANA's network development, in large part driven by the expansion of international slots at Tokyo's Haneda Airport. ANA received an allocation of 11 new slots, which it is using to switch some flights from Narita Airport to Haneda, and also to launch new routes.

So far, the carrier has announced routes for 10 of the 11 slots, which can be used for services beginning March 30. Regulators earmarked the slots for certain international markets, and the single slot remaining to be allocated by ANA is for service to China.

Haneda Airport slots are considered highly desirable because the facility is closer to downtown Tokyo than Narita. The airport has traditionally been used for domestic services, but runway and terminal expansion in recent years has enabled the government to distribute slots for international flights. The latest round of allocations occurred in October, and ANA was granted 11 slots while JAL was given five. Government officials said they took into account the fact that JAL received significant state aid when it reorganized under bankruptcy protection in 2010-11.