The FTSE 100 rose 0.5% to 5,757.22 in early trading, despite negative company announcements across various sectors.
News BA has made a new proposal to cabin crew in a bid to resolve a year-long dispute involving extended strikes, sending its shares up 3.4% to 287.5p.
InterContinental Hotels Group also rose, by 2.7% to £12.03.
Among the losers, Tullow Oil declined 3.5% to £12.09 on news its well on Ghana's coastline had hit problems.
BAE Systems fell 0.5% to 348p after forecasting reduced growth this year as the government is expected to cut defence spending.
TUI Travel's share price fell dramatically, dropping 6.6% to 215.3p after it said it had to restate its results for 2008/2009.
In the US, the Dow Jones closed up 129.4 points, or 1.2%, at 11,107.97 on healthy earnings reports, while the S&P 500 rose 1.1%.
Yahoo and Boeing profits beat estimates, driving them 2.1% and 3.3% higher respectively, while airline Delta rose 10.8% and rival US Air gained 7.4%, also on better than expected profits.
In Asia the Nikkei 225 was flat at 9,376.48 points.
China Mobile fell 2.3%, while Hana Financial Group plunged 7.3%.
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