I returned to my seat. I was craning my neck trying to follow the hunt when suddenly I heard from my feet a distressed chitter of recognition and welcome, and Mij bounded on to my knee and began to nuzzle my face and my neck.

Explanation:

 

The narrator returned to his seat after the flight hostess asked him to do so, and he immediately began to seek around for Mij. It wasn't until Mij crept up his knee to reach his face that he heard some chittering. Mij had come back.

 

Meanings of difficult words:

 
Sl. No
Words
Meanings
1
ValleyA low area of land between hills or mountains, typically with a river or stream flowing through it
2
CrestThe top of a mountain or hill
3
RipeHaving arrived at the fitting stage or time for a particular action or purpose
4
DownpourA heavy fall of rain
5
ShowerA brief and usually light fall of rain, hail, sleet, or snow
6
IntimatelyIn a way that involves detailed knowledge
Reference:

National Council of Educational Research and Training (2007). First Flight. Mijbil the Otter - Gavin Maxwell (pp. 102 - 110). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi..