UPDATE 1-UK budget carrier BMI Baby to cut jobs and routes

* Up to 158 pilot, crew, management jobs to go

* Says will reduce routes and fleet size

(Adds union comment)

LONDON, Nov 4 (Reuters) - Low-cost airline BMI Baby, part of the BMI Group, on Wednesday said it would to cut up to 158 jobs and reduce the number of routes it flies due to the ongoing impact of the economic downturn.

The airline, owned by German carrier Lufthansa AG (LHAG.DE: Quote, Profile, Research), said 54 pilot and 82 cabin crew positions at Britain's Birmingham, Manchester and Cardiff airports were "at risk of redundancy", as were an additional 22 management and support positions at its head office and at other airport bases.

BMI Baby also said it would reduce its fleet size by five aircraft in 2010 from the current 17 due to "the worst economic recession in recent times and record losses in the aviation industry".

Britain's Unite union said in a statement that it would be working to stop compulsory redundancies at the airline.

It comes amid growing labour tensions at British Airways (BAY.L: Quote, Profile, Research) which have raised the spectre of possible strike action over Christmas. [ID:nLU695323]

Earlier this week the International Air Transport Association said it still expected airlines to lose $11 billion this year, following a $17 billion loss last year, and warned that with jet fuel on the rise, cash flows would be under pressure. [ID:nL3308270]