Due to runway maintenance, TIA has notified that Airport will be closed from 22:30 to 6: 30 effectively from September 1 to December 31, 2019. During the above mentioned period there will be traffic congestion at Kathmandu Airport which leads to Air Traffic Hold, flight delay and high possibility for flight cancellation due to flight start up queue, therefore for smooth operation of Lukla flight, the flights will operate from Ramechhap airport effectively from October 1st to December 31st, 2019.

The same arrangement was used during the spring season and arrangement was accomplished successfully.

During tourist season, Lukla airport is the busiest airport among the STOL airfields operated from Kathmandu. Autumn being one of the best trekking seasons in Nepal, the airport is the busiest compared to other times of the year. In order to avoid these congestion and minimize the load of Airport, all the flights to Lukla are diverted to Ramechhap for smooth operation.  

All you need to know about Ramechhap airport:
Ramechhap airport is a small airstrip 140 Km (85miles) from Kathmandu. The airport was opened in October 1979. The airport is also known as Manthali Airport as it is situated in Manthali. Manthali is capital of Ramechhap district. The airport used to have grass or clay runway before but in 2015 it was renovated to concrete runway. As of 2019, the airport has started flights to Lukla due to ongoing runway renovation in Tribhuwan International Airport. The flight duration from Ramechhap to Lukla is about 20 minutes.

Everything you need to know regarding the changes:

For all the traveler trekking with Himalayan Social Journey-
On the day of arrival in Kathmandu, you will meet Himalayan Social Journey team and have small orientation about the trip at the Hotel. Then with the team around late afternoon, you will be driven to Ramechhap. The drive is about 4 hours in a private vehicle. You will be staying at the Hotel in Ramechhap. And the next morning, you will wake up early to take the flight to Lukla.
To those who cannot go to Ramechhap on the arrival day, you will stay overnight in Kathmandu. The next day at 3 am you will wake up to take a private transportation to Ramechhap in order to catch the flight.  
For all the traveler trekking solo or without trekking agency-
They can stay overnight in Kathmandu, drive to Ramechaap next day and on the third day they can take flight to Lukla.

How to avoid this alteration?
If you want to avoid this hassle, then you have the option of taking Helicopter to Lukla. Helicopter will continue to fly from Kathmandu to Lukla. We are able to arrange the Helicopter, if you wish to take a helicopter ride to Lukla. Please let us know if you want us to arrange this alternative.
For one way helicopter ride to Lukla per person is USD 350.

Some of the frequently asked questions regarding this diversion:

How is Ramechhap Airport good option?
There is a very less chance of flight cancellation since flight is just 15 -20 min from Ramechhap to Lukla. This means its even faster to reach Lukla from Ramechhap. If the weather is good, a lot of flights can take off and good number of guest can reach Lukla in short amount of time. Although, the airport need renovation in different sectors but it is far better option than waiting in the crowded airport of Kathmandu and missing the good view from the window. 
Are there any fixed wing flights from Kathmandu to Lukla?
As much as you would like to avoid going to Ramechhap, it is far better option to take flight from Ramechhap airport than wait in the traffic of flights in Kathmandu. There are one or two flights taking off occasionally in a day from Kathmandu to Lukla but it can be cancelled or delayed without any proper information.
If you have further questions about this, please feel free to reach out to Support team at Himalayan Social Journey.