* Air Canada says sees advance bookings in all sectors
* Analyst says Q1 traffic weaker than expected
* Load factor down to 79.5 pct from 82.1 pct in March (Adds analyst, CEO comments)
VANCOUVER, April 6 (Reuters) - Air Canada ACa.TO ACb.TO said on Wednesday it flew emptier planes in March and that it expects a key earnings measure to be flat through the first six months of the year.
"We expect EBITDAR (earnings before interest, taxes, depreciation and aircraft rent) levels for the first half of 2011 to be approximately at the same level as the first half of 2010," Chief Executive Calin Rovinescu said in a statement.
The forecast was similar to what had been expected, PI Financial analyst Chris Murray said, adding that the third quarter was usually the airline's strongest earnings period.
Murray said he was encouraged by Rovinescu's statement that Air Canada was seeing advance bookings in all sectors, including the Atlantic and Pacific.
The country's biggest airline also said traffic across its routes increased 4.2 percent in March but was outflanked by a system-wide capacity increase of 7.6 percent.
That resulted in a system load factor of 79.5 percent, down from 82.1 percent in March 2010.
"First-quarter traffic data was slightly weaker than what I was looking for," Murray said, blaming a drop in February, which was weaker than a year ago when the Vancouver Winter Olympics fueled traffic numbers.
Rovinescu said the market had been absorbing the fare increases and surcharges Air Canada implemented recently due to higher fuel costs, echoing a similar statement on Tuesday by rival WestJet Airlines Ltd (WJA.TO).
WestJet said it flew fuller planes in March even as it increased ticket prices in the face of a recent surge in oil prices. [ID:nN05177991] (Reporting by Nicole Mordant; editing by Peter Galloway and Rob Wilson)