City and town officials are voicing surprise over Governor Dannel P. Malloy’s plan to slash local property taxes on vehicles, questioning how their municipalities will make up the lost revenue. Malloy’s two-year, $43.8 billion plan calls for exempting the first $20,000 of a vehicle’s assessed value from the local property tax. For someone who owns a car with a market value under $28,571, they would pay no property taxes. If enacted, the plan means a revenue loss of approximately $560 million a year. While the funding is not made up elsewhere in the budget, Malloy’s budget director insisted that cities and towns will be funded at the same level.