Broker Liberum has lifted its target price for budget airline Easyjet from 1,650p to 1,725p and repeated its 'buy' recommendation, hailing the company's effort to adapt to an "inflationary world".Analyst Gerald Khoo said while non-fuel unit cost inflation is set to rise, Easyjet's so-called 'lean' cost-saving initiatives and additional larger A320 aircraft "will be crucial in mitigating this".Credit Suisse has lowered its rating for UK outsourcing group Serco from 'neutral' to 'underperform' and more than halved its target price from 325p to 142p, saying that the shares are "too expensive"."After the unveiling of significant onerous contract provisions and the risk of more to come, we see huge uncertainty around the operational cash flows of the business," the bank said.Westhouse Securities has called for investors in the oil and gas sector to be a "bit more patient" with oil prices currently rumbling along at multi-year lows, as it highlighted buying opportunities in the sector.With some equities having been "oversold", Westhouse said that many stocks will be able to weather the short-term pressure on oil and also have near-term catalysts coming up. These are Ithaca Energy, Genel Energy, Enquest and Circle Oil - all of which are rated 'buy'.