SIA stock price shot up by 10% from $5.06 to $5.58 on 11 October 2021, driven by optimism for the airline following the move to establised vaccinnated travel lines (VTL) into Singapore. 

The stock price has corrected to $5.30 on 20 October.

Here are the financial indicators:
Source: 
https://finance.yahoo.com/quote/C6L.SI?p=C6L.SI 
Go to Summary, Statistics and Financial tab

PE ratio - NA (the company is showing losses)
Dividend yield - NA (not paying any dividend)
Book value per share: $5.36
Current share price (12 Oct 21) $5.30
Price to book: 1.03
Total debt to equity: 92.17%

Net income for Y/E March 2021: Loss $4,270,000
Normalized income: Loss $2,132,000 (I suppose the difference is due to non recurring items, e.g. forward contract on fuel or write-off of assets).
Working capital $3,958,000

I expect SIA to continue operating at a big loss for at least a year after the opening up of air travel. Singapore is still under travel restriction due to high covid cases. The incoming travel should be low.

The fuel price is likely to be at a high level for the next few months, due to the global energy crisis.

I do not have any holding of SIA shares now. I will not invest in this stock for the foreseeable future.

Caution - This is my personal opinion. I an not giving investment advice.